Dromaeosauridae

Dromaeosauridae (/ˌdrɒmi.əˈsɔːrɪdiː/) is a family of feathered coelurosaurian theropod dinosaurs. They were generally small to medium-sized feathered carnivores that flourished in the Cretaceous Period. The name Dromaeosauridae means 'running lizards', from Greek ('), meaning 'running at full speed, swift', and ('), meaning 'lizard'. In informal usage, they are often called raptors (after Velociraptor), a term popularized by the film Jurassic Park; several genera include the term "raptor" directly in their name, and popular culture has come to emphasize their bird-like appearance and speculated bird-like behavior.

Dromaeosaurid fossils have been found across the globe in North America, Europe, Africa, Asia, South America and Antarctica, with some fossils giving credence to the possibility that they inhabited Australia as well. The earliest body fossils are known from the Early Cretaceous (145-140 million years ago, and they survived until the end of the Cretaceous (Maastrichtian stage, 66 ma), existing until the Cretaceous–Paleogene extinction event. The presence of dromaeosaurids as early as the Middle Jurassic has been suggested by the discovery of isolated fossil teeth, though no dromaeosaurid body fossils have been found from this period.

## Description

### Technical diagnosis

Dromaeosaurids are diagnosed by the following features; short T-shaped frontals that form the rostral boundary of the supratemporal fenestra; a caudolateral overhanging shelf of the squamosal; a lateral process of the quadrate that contacts the quadratojugal; raised, stalked, parapophyses on the dorsal vertebrae, a modified pedal digit II; chevrons and prezygapophysis of the caudal vertebrae elongate and spanning several vertebrae; the presence of a subglenoid fossa on the coracoid.

### Size and general build

Dromaeosaurids were small to medium-sized dinosaurs, ranging from 1.5–2.07 metres (4.9–6.8 ft) in length (in the case of Velociraptor) to approaching or over 6 m (20 ft) (in Utahraptor, Dakotaraptor and Achillobator). Large size appears to have evolved at least twice among dromaeosaurids; once among the dromaeosaurines Utahraptor and Achillobator, and again among the unenlagiines (Austroraptor, which measured 5–6 m (16–20 ft) long). A possible third lineage of giant dromaeosaurids is represented by isolated teeth found on the Isle of Wight, England. The teeth belong to an animal the size of the dromaeosaurine Utahraptor, but they appear to belong to velociraptorines, judging by the shape of the teeth.

The distinctive dromaeosaurid body plan helped to rekindle theories that dinosaurs may have been active, fast, and closely related to birds. Robert Bakker's illustration for John Ostrom's 1969 monograph, showing the dromaeosaurid Deinonychus in a fast run, is among the most influential paleontological reconstructions in history. The dromaeosaurid body plan includes a relatively large skull, serrated teeth, narrow snout (an exception being the derived dromaeosaurines), and forward-facing eyes which indicate some degree of binocular vision.

Dromaeosaurids, like most other theropods, had a moderately long S-curved neck, and their trunk was relatively short and deep. Like other maniraptorans, they had long arms that could be folded against the body in some species, and relatively large hands with three long fingers (the middle finger being the longest and the first finger being the shortest) ending in large claws. The dromaeosaurid hip structure featured a characteristically large pubic boot projecting beneath the base of the tail. Dromaeosaurid feet bore a large, recurved claw on the second toe. Their tails were slender, with long, low, vertebrae lacking transverse process and neural spines after the 14th caudal vertebra. Ossified uncinate processes of ribs have been identified in several dromaeosaurids.

### Foot

Like other theropods, dromaeosaurids were bipedal; that is, they walked on their hind legs. However, whereas most theropods walked with three toes contacting the ground, fossilized footprint tracks confirm that many early paravian groups, including the dromaeosaurids, held the second toe off the ground in a hyperextended position, with only the third and fourth toes bearing the weight of the animal. This is called functional didactyly. The enlarged second toe bore an unusually large, curved, falciform (sickle-shaped, alt. drepanoid) claw (held off the ground or 'retracted' when walking), which is thought to have been used in capturing prey and climbing trees (see "Claw function" below). This claw was especially blade-like in the large-bodied predatory eudromaeosaurs. One possible dromaeosaurid species, Balaur bondoc, also possessed a first toe which was highly modified in parallel with the second. Both the first and second toes on each foot of B. bondoc were also held retracted and bore enlarged, sickle-shaped claws.

### Tail

Dromaeosaurids had long tails. Most of the tail vertebrae bore bony, rod-like extensions (called prezygapophyses), as well as bony tendons in some species. In his study of Deinonychus, Ostrom proposed that these features stiffened the tail so that it could only flex at the base, and the whole tail would then move as a single, rigid, lever. However, one well-preserved specimen of Velociraptor mongoliensis (IGM 100/986) has an articulated tail skeleton that is curved horizontally in a long S-shape. This suggests that, in life, the tail could bend from side to side with a substantial degree of flexibility. It has been proposed that this tail was used as a stabilizer or counterweight while running or in the air; in Microraptor, an elongate diamond-shaped fan of feathers is preserved on the end of the tail. This may have been used as an aerodynamic stabilizer and rudder during gliding or powered flight (see "Flight and gliding" below).

### Feathers

There is a large body of evidence showing that dromaeosaurids were covered in feathers. Some dromaeosaurid fossils preserve long, pennaceous feathers on the hands and arms (remiges) and tail (rectrices), as well as shorter, down-like feathers covering the body. Other fossils, which do not preserve actual impressions of feathers, still preserve the associated bumps on the forearm bones where long wing feathers would have attached in life. Overall, this feather pattern looks very much like Archaeopteryx.

The first known dromaeosaurid with definitive evidence of feathers was Sinornithosaurus, reported from China by Xu et al. in 1999. Many other dromaeosaurid fossils have been found with feathers covering their bodies, some with fully developed feathered wings. Microraptor even shows evidence of a second pair of wings on the hind legs. While direct feather impressions are only possible in fine-grained sediments, some fossils found in coarser rocks show evidence of feathers by the presence of quill knobs, the attachment points for wing feathers possessed by some birds. The dromaeosaurids Rahonavis and Velociraptor have both been found with quill knobs, showing that these forms had feathers despite no impressions having been found. In light of this, it is most likely that even the larger ground-dwelling dromaeosaurids bore feathers, since even flightless birds today retain most of their plumage, and relatively large dromaeosaurids, like Velociraptor, are known to have retained pennaceous feathers. Though some scientists had suggested that the larger dromaeosaurids lost some or all of their insulatory covering, the discovery of feathers in Velociraptor specimens has been cited as evidence that all members of the family retained feathers.

More recently, the discovery of Zhenyuanlong established the presence of a full feathered coat in relatively large dromaeosaurids. Additionally, the animal displays proportionally large, aerodynamic wing feathers, as well as a tail-spanning fan, both of which are unexpected traits that may offer an understanding of the integument of large dromaeosaurids. Dakotaraptor is an even larger dromaeosaurid species with evidence of feathers, albeit indirect in the form of quill knobs.

## Classification

### Relationship with birds

Dromaeosaurids share many features with early birds (clade Avialae or Aves). The precise nature of their relationship to birds has undergone a great deal of study, and hypotheses about that relationship have changed as large amounts of new evidence became available. As late as 2001, Mark Norell and colleagues analyzed a large survey of coelurosaur fossils and produced the tentative result that dromaeosaurids were most closely related to birds, with troodontids as a more distant outgroup. They even suggested that Dromaeosauridae could be paraphyletic relative to Avialae.[^1] In 2002, Hwang and colleagues utilized the work of Norell et al., including new characters and better fossil evidence, to determine that birds (avialans) were better thought of as cousins to the dromaeosaurids and troodontids. The consensus of paleontologists is that there is not yet enough evidence to determine whether any dromaeosaurids could fly or glide, or whether they evolved from ancestors that could.

### Alternative theories and flightlessness

Dromaeosaurids are so bird-like that they have led some researchers to argue that they would be better classified as birds. First, since they had feathers, dromaeosaurids (along with many other coelurosaurian theropod dinosaurs) are "birds" under traditional definitions of the word "bird", or "Aves", that are based on the possession of feathers. However, other scientists, such as Lawrence Witmer, have argued that calling a theropod like Caudipteryx a bird because it has feathers may stretch the word past any useful meaning.

At least two schools of researchers have proposed that dromaeosaurids may actually be descended from flying ancestors. Hypotheses involving a flying ancestor for dromaeosaurids are sometimes called "Birds Came First" (BCF). George Olshevsky is usually credited as the first author of BCF. In his own work, Gregory S. Paul pointed out numerous features of the dromaeosaurid skeleton that he interpreted as evidence that the entire group had evolved from flying, dinosaurian ancestors, perhaps an animal like Archaeopteryx. In that case, the larger dromaeosaurids were secondarily flightless, like the modern ostrich. In 1988, Paul suggested that dromaeosaurids may actually be more closely related to modern birds than to Archaeopteryx. By 2002, however, Paul placed dromaeosaurids and Archaeopteryx as the closest relatives to one another.

In 2002, Hwang et al. found that Microraptor was the most primitive dromaeosaurid. Xu and colleagues in 2003 cited the basal position of Microraptor, along with feather and wing features, as evidence that the ancestral dromaeosaurid could glide. In that case the larger dromaeosaurids would be secondarily terrestrial—having lost the ability to glide later in their evolutionary history.

Also in 2002, Steven Czerkas described Cryptovolans, though it is a probable junior synonym of Microraptor. He reconstructed the fossil inaccurately with only two wings and thus argued that dromaeosaurids were powered fliers, rather than passive gliders. He later issued a revised reconstruction in agreement with that of Microraptor

Other researchers, like Larry Martin, have proposed that dromaeosaurids, along with all maniraptorans, were not dinosaurs at all. Martin asserted for decades that birds were unrelated to maniraptorans, but in 2004 he changed his position, agreeing that the two were close relatives. However, Martin believed that maniraptorans were secondarily flightless birds, and that birds did not evolve from dinosaurs, but rather from non-dinosaurian archosaurs.

In 2005, Mayr and Peters described the anatomy of a very well preserved specimen of Archaeopteryx, and determined that its anatomy was more like non-avian theropods than previously understood. Specifically, they found that Archaeopteryx had a primitive palatine, unreversed hallux, and hyper-extendable second toe. Their phylogenetic analysis produced the controversial result that Confuciusornis was closer to Microraptor than to Archaeopteryx, making the Avialae a paraphyletic taxon. They also suggested that the ancestral paravian was able to fly or glide, and that the dromaeosaurids and troodontids were secondarily flightless (or had lost the ability to glide). Corfe and Butler criticized this work on methodological grounds.

A challenge to all of these alternative scenarios came when Turner and colleagues in 2007 described a new dromaeosaurid, Mahakala, which they found to be the most basal and most primitive member of the Dromaeosauridae, more primitive than Microraptor. Mahakala had short arms and no ability to glide. Turner et al. also inferred that flight evolved only in the Avialae, and these two points suggested that the ancestral dromaeosaurid could not glide or fly. Based on this cladistic analysis, Mahakala suggests that the ancestral condition for dromaeosaurids is non-volant. However, in 2012, an expanded and revised study incorporating the most recent dromaeosaurid finds recovered the Archaeopteryx-like Xiaotingia as the most primitive member of the clade Dromaeosauridae, which appears to suggest the earliest members of the clade may have been capable of flight.

### Taxonomy

The authorship of the family Dromaeosauridae is credited to William Diller Matthew and Barnum Brown, who erected it as a subfamily (Dromaeosaurinae) of the family Deinodontidae in 1922, containing only the new genus Dromaeosaurus.

The subfamilies of Dromaeosauridae frequently shift in content based on new analysis, but typically consist of the following groups. A number of dromaeosaurids have not been assigned to any particular subfamily, often because they are too poorly preserved to be placed confidently in phylogenetic analysis (see section Phylogeny below) or are indeterminate, being assigned to different groups depending on the methodology employed in different papers. The most basal known subfamily of dromaeosaurids is Halszkaraptorinae, a group of bizarre creatures with long fingers and necks, a large number of small teeth, and possible semiaquatic habits. Another enigmatic group, Unenlagiinae, is the most poorly supported subfamily of dromaeosaurids and it is possible that some or all of its members belong outside of Dromaeosauridae. The larger, ground-dwelling members like Buitreraptor and Unenlagia show strong flight adaptations, although they were probably too large to 'take off'. One possible member of this group, Rahonavis, is very small, with well-developed wings that show evidence of quill knobs (the attachment points for flight feathers) and it is very likely that it could fly. The next most primitive clade of dromaeosaurids is the Microraptoria. This group includes many of the smallest dromaeosaurids, which show adaptations for living in trees. All known dromaeosaurid skin impressions hail from this group and all show an extensive covering of feathers and well-developed wings. Like the unenlagiines, some species may have been capable of active flight. The most advanced subgroup of dromaeosaurids, Eudromaeosauria, includes stocky and short-legged genera which were likely ambush hunters. This group includes Velociraptorinae, Dromaeosaurinae, and in some studies a third group: Saurornitholestinae. The subfamily Velociraptorinae has traditionally included Velociraptor, Deinonychus, and Saurornitholestes, and while the discovery of Tsaagan lent support to this grouping, the inclusion of Deinonychus, Saurornitholestes, and a few other genera is still uncertain. The Dromaeosaurinae is usually found to consist of medium to giant-sized species, with generally box-shaped skulls (the other subfamilies generally have narrower snouts).

The following classification of the various genera of dromaeosaurids follows the table provided in Holtz, 2011 unless otherwise noted.

- Family Dromaeosauridae
  - Nuthetes
  - Pamparaptor
  - Variraptor
  - Pyroraptor
  - Zhenyuanlong
  - Daurlong
  - Subfamily Halszkaraptorinae
    - Halszkaraptor
    - Mahakala
    - Hulsanpes
    - Natovenator
  - Subfamily Unenlagiinae
    - Ornithodesmus
    - Austroraptor
    - Rahonavis
    - Unenlagia
    - Buitreraptor
    - Neuquenraptor
    - Unquillosaurus
    - Ypupiara
  - Subfamily Microraptorinae
    - Shanag
    - Tianyuraptor
    - Graciliraptor
    - Changyuraptor
    - Hesperonychus
    - Microraptor
    - Sinornithosaurus
    - Wulong
    - Zhongjianosaurus
  - Node Eudromaeosauria
    - Deinonychus
    - Dineobellator
    - Vectiraptor
    - Subfamily Saurornitholestinae
      - Bambiraptor
      - Saurornitholestes
      - Atrociraptor
      - Acheroraptor?
    - Subfamily Velociraptorinae
      - Luanchuanraptor?
      - Linheraptor?
      - Velociraptor
      - Tsaagan?
      - Adasaurus?
      - Shri
      - Kansaignathus
      - Kuru
    - Subfamily Dromaeosaurinae
      - Achillobator?
      - Itemirus?
      - Dromaeosaurus
      - Dakotaraptor?
      - Dromaeosauroides?
      - Utahraptor?
      - Yurgovuchia?

### Phylogeny

Dromaeosauridae was first defined as a clade by Paul Sereno in 1998, as the most inclusive natural group containing Dromaeosaurus but not Troodon, Ornithomimus or Passer. The various "subfamilies" have also been re-defined as clades, usually defined as all species closer to the groups namesake than to Dromaeosaurus or any namesakes of other sub-clades (for example, Makovicky defined the clade Unenlagiinae as all dromaeosaurids closer to Unenlagia than to Velociraptor). The Microraptoria is the only dromaeosaurid sub-clade not converted from a subfamily. Senter and colleagues expressly coined the name without the subfamily suffix -inae to avoid perceived issues with erecting a traditional family-group taxon, should the group be found to lie outside dromaeosauridae proper. Sereno offered a revised definition of the sub-group containing Microraptor to ensure that it would fall within Dromaeosauridae, and erected the subfamily Microraptorinae, attributing it to Senter et al., though this usage has only appeared on his online TaxonSearch database and has not been formally published. The extensive cladistic analysis conducted by Turner et al. (2012) further supported the monophyly of Dromaeosauridae.

The cladogram below follows a 2015 analysis by DePalma et al. using updated data from the Theropod Working Group.

Another cladogram constructed below follows the phylogenetic analysis conducted in 2017 by Cau et al. using the updated data from the Theropod Working Group in their description of Halszkaraptor.

## Paleobiology

### Senses

Comparisons between the scleral rings of several dromaeosaurids (Microraptor, Sinornithosaurus, and Velociraptor) and modern birds and reptiles indicate that some dromaeosaurids (including Microraptor and Velociraptor) may have been nocturnal predators, while Sinornithosaurus is inferred to be cathemeral (active throughout the day at short intervals). However, the discovery of iridescent plumage in Microraptor has cast doubt on the inference of nocturnality in this genus, as no modern birds that have iridescent plumage are known to be nocturnal.

Studies of the olfactory bulbs of dromaeosaurids reveal that they had similar olfactory ratios for their size to other non-avian theropods and modern birds with an acute sense of smell, such as tyrannosaurids and the turkey vulture, probably reflecting the importance of the olfactory sense in the daily activities of dromaeosaurids such as finding food.

### Feeding

Dromaeosaurid feeding was discovered to be typical of coelurosaurian theropods, with a characteristic "puncture and pull" feeding method. Studies of wear patterns on the teeth of dromaeosaurids by Angelica Torices et al. indicate that dromaeosaurid teeth share similar wear patterns to those seen in the Tyrannosauridae and Troodontidae. However, microwear on the teeth indicated that dromaeosaurids likely preferred larger prey items than the troodontids they often shared their environment with. Such dietary differentiations likely allowed them to inhabit the same environment. The same study also indicated that dromaeosaurids such as Dromaeosaurus and Saurornitholestes (two dromaeosaurids analyzed in the study) likely included bone in their diet and were better adapted to handle struggling prey while troodontids, equipped with weaker jaws, preyed on softer animals and prey items such as invertebrates and carrion.

### Claw function

There is currently disagreement about the function of the enlarged "sickle claw" on the second toe. When John Ostrom described it for Deinonychus in 1969, he interpreted the claw as a blade-like slashing weapon, much like the canines of some saber-toothed cats, used with powerful kicks to cut into prey. Adams (1987) suggested that the talon was used to disembowel large ceratopsian dinosaurs. The interpretation of the sickle claw as a killing weapon applied to all dromaeosaurids. However, Manning et al. argued that the claw instead served as a hook, reconstructing the keratinous sheath with an elliptical cross section, instead of the previously inferred inverted teardrop shape. In Manning's interpretation, the second toe claw would be used as a climbing aid when subduing bigger prey and also as a stabbing weapon.

Ostrom compared Deinonychus to the ostrich and cassowary. He noted that the bird species can inflict serious injury with the large claw on the second toe. The cassowary has claws up to 125 millimetres (4.9 in) long. Ostrom cited Gilliard (1958) in saying that they can sever an arm or disembowel a man. Kofron (1999 and 2003) studied 241 documented cassowary attacks and found that one human and two dogs had been killed, but no evidence that cassowaries can disembowel or dismember other animals. Cassowaries use their claws to defend themselves, to attack threatening animals, and in agonistic displays such as the Bowed Threat Display. The seriema also has an enlarged second toe claw, and uses it to tear apart small prey items for swallowing.

Phillip Manning and colleagues (2009) attempted to test the function of the sickle claw and similarly shaped claws on the forelimbs. They analyzed the bio-mechanics of how stresses and strains would be distributed along the claws and into the limbs, using X-ray imaging to create a three-dimensional contour map of a forelimb claw from Velociraptor. For comparison, they analyzed the construction of a claw from a modern predatory bird, the eagle owl. They found that, based on the way that stress was conducted along the claw, they were ideal for climbing. The scientists found that the sharpened tip of the claw was a puncturing and gripping instrument, while the curved and expanded claw base helped transfer stress loads evenly. The Manning team also compared the curvature of the dromaeosaurid "sickle claw" on the foot with curvature in modern birds and mammals. Previous studies had shown that the amount of curvature in a claw corresponded to what lifestyle the animal has: animals with strongly curved claws of a certain shape tend to be climbers, while straighter claws indicate ground-dwelling lifestyles. The sickle claws of the dromaeosaurid Deinonychus have a curvature of 160 degrees, well within the range of climbing animals. The forelimb claws they studied also fell within the climbing range of curvature.

Paleontologist Peter Mackovicky commented on the Manning team's study, stating that small, primitive dromaeosaurids (such as Microraptor) were likely to have been tree-climbers, but that climbing did not explain why later, gigantic dromaeosaurids such as Achillobator retained highly curved claws when they were too large to have climbed trees. Mackovicky speculated that giant dromaeosaurids may have adapted the claw to be used exclusively for latching on to prey.

In 2009 Phil Senter published a study on dromaeosaurid toes and showed that their range of motion was compatible with the excavation of tough insect nests. Senter suggested that small dromaeosaurids such as Rahonavis and Buitreraptor were small enough to be partial insectivores, while larger genera such as Deinonychus and Neuquenraptor could have used this ability to catch vertebrate prey residing in insect nests. However, Senter did not test whether the strong curvature of dromaeosaurid claws was also conducive to such activities.

In 2011, Denver Fowler and colleagues suggested a new method by which dromaeosaurids may have taken smaller prey. This model, known as the "raptor prey restraint" (RPR) model of predation, proposes that dromaeosaurids killed their prey in a manner very similar to extant accipitrid birds of prey: by leaping onto their quarry, pinning it under their body weight, and gripping it tightly with the large, sickle-shaped claws. Like accipitrids, the dromaeosaurid would then begin to feed on the animal while still alive, until it eventually died from blood loss and organ failure. This proposal is based primarily on comparisons between the morphology and proportions of the feet and legs of dromaeosaurids to several groups of extant birds of prey with known predatory behaviors. Fowler found that the feet and legs of dromaeosaurids most closely resemble those of eagles and hawks, especially in terms of having an enlarged second claw and a similar range of grasping motion. The short metatarsus and foot strength, however, would have been more similar to that of owls. The RPR method of predation would be consistent with other aspects of dromaeosaurid anatomy, such as their unusual dentition and arm morphology. The arms, which could exert a lot of force but were likely covered in long feathers, may have been used as flapping stabilizers for balance while atop a struggling prey animal, along with the stiff counterbalancing tail. Dromaeosaurid jaws, thought by Fowler and colleagues to be comparatively weak, would have been useful for eating prey alive but not as useful for quick, forceful dispatch of the prey. These predatory adaptations working together may also have implications for the origin of flapping in paravians.

In 2019, Peter Bishop reconstructed the leg skeleton and musculature of Deinonychus by using three-dimensional models of muscles, tendons, and bones. With the addition of mathematical models and equations, Bishop simulated the conditions that would provide maximum force at the tip of the sickle claw and therefore the most likely function. Among the proposed modes of the sickle claw use are: kicking to cut, slash or disembowel prey; for gripping onto the flanks of prey; piercing aided by body weight; to attack vital areas of the prey; to restrain prey; intra- or interspecific competition; and digging out prey from hideouts. The results obtained by Bishop showed that a crouching posture increased the claw forces, however, these forces remained relatively weak indicating that the claws were not strong enough to be used in slashing strikes. Rather than being used for slashing, the sickle claws were more likely to be useful in flexed leg angles such as restraining prey and stabbing prey at close quarters. These results are consistent with the Fighting Dinosaurs specimen, which preserves a Velociraptor and Protoceratops locked in combat, with the former gripping onto the other with its claws in a non-extended leg posture. Despite the obtained results, Bishop considered that the capabilities of the sickle claw could have varied within taxa given that among dromaeosaurids, Adasaurus had an unusually smaller sickle claw that retained the characteristic ginglymoid—a structure divided in two parts—and hyperextensible articular surface of the penultimate phalange. He could neither confirm nor disregard that the pedal digit II could have loss or retain its functionally.

A 2020 study by Gianechini et al., also indicates that velociraptorines, dromaeosaurines and other eudromaeosaurs in Laurasia differed greatly in their locomotive and killing techniques from the unenlagiine dromaeosaurids of Gondwana. The shorter second phalanx in the second digit of the foot allowed for increased force to be generated by that digit, which, combined with a shorter and wider metatarsus, and a noticeable marked hinge‐like morphology of the articular surfaces of metatarsals and phalanges, possibly allowed eudromaeosaurs to exert a greater gripping strength than unenlagiines, allowing for more efficient subduing and killing of large prey. In comparison, the unenlagiine dromaeosaurids had a longer and slender subarctometatarsus, and less well‐marked hinge joints, a trait that possibly gave them greater cursorial capacities and allowed for greater speed. Additionally, the longer second phalanx of the second digit allowed unenlagiines fast movements of their feet's second digits to hunt smaller and more elusive types of prey. These differences in locomotor and predatory specializations may have been a key feature that influenced the evolutionary pathways that shaped both groups of dromaeosaurs in the northern and southern hemispheres.

### Group behavior

Deinonychus fossils have been uncovered in small groups near the remains of the herbivore Tenontosaurus, a larger ornithischian dinosaur. This had been interpreted as evidence that these dromaeosaurids hunted in coordinated packs like some modern mammals. However, not all paleontologists found the evidence conclusive, and a subsequent study published in 2007 by Roach and Brinkman suggests that the Deinonychus may have actually displayed a disorganized mobbing behavior. Modern diapsids, including birds and crocodiles (the closest relatives of dromaeosaurids), display minimal long-term cooperative hunting (except the aplomado falcon and Harris's hawk); instead, they are usually solitary hunters, either joining forces time to time to increase hunting success (as crocodilians sometimes do), or are drawn to previously killed carcasses, where conflict often occurs between individuals of the same species. For example, in situations where groups of Komodo dragons are eating together, the largest individuals eat first and might attack smaller Komodo dragons that attempt to feed; if the smaller animal dies, it is usually cannibalized. When this information is applied to the sites containing putative pack-hunting behavior in dromaeosaurids, it appears somewhat consistent with a Komodo dragon-like feeding strategy. Deinonychus skeletal remains found at these sites are from subadults, with missing parts that may have been eaten by other Deinonychus, which a study by Roach et al. presented as evidence against the idea that the animals cooperated in the hunt. Different dietary preferences between juvenile and adult Deinonychus published in 2020 indicate that the animal did not exhibit complex, cooperative behavior seen in pack-hunting animals. Whether this extended to other dromaeosaurs is currently unknown. A third possible option is that dromaeosaurids did not exhibit long-term cooperative behaviour, but did show short-term cooperative behaviour as seen in crocodilians, which display both true cooperation and competition for prey.

In 2001, multiple Utahraptor specimens ranging in age from fully grown adult to tiny three-foot-long baby were found at a site considered by some to be a quicksand predator trap. Some consider this as evidence of family hunting behaviour; however, the full sandstone block is yet to be opened and researchers are unsure as to whether or not the animals died at the same time.

In 2007, scientists described the first known extensive dromaeosaurid trackway, in Shandong, China. In addition to confirming the hypothesis that the sickle claw was held retracted off the ground, the trackway (made by a large, Achillobator-sized species) showed evidence of six individuals of about equal size moving together along a shoreline. The individuals were spaced about one meter apart, traveling in the same direction and walking at a fairly slow pace. The authors of the paper describing these footprints interpreted the trackways as evidence that some species of dromaeosaurids lived in groups. While the trackways clearly do not represent hunting behavior, the idea that groups of dromaeosaurids may have hunted together, according to the authors, could not be ruled out.

### Flying and gliding

The forearms of dromaeosaurids appear well adapted to resisting the torsional and bending stresses associated with flapping and gliding, and the ability to fly or glide has been suggested for at least five dromaeosaurid species. The first, Rahonavis ostromi (originally classified as avian bird, but found to be a dromaeosaurid in later studies) may have been capable of powered flight, as indicated by its long forelimbs with evidence of quill knob attachments for long sturdy flight feathers. The forelimbs of Rahonavis were more powerfully built than Archaeopteryx, and show evidence that they bore strong ligament attachments necessary for flapping flight. Luis Chiappe concluded that, given these adaptations, Rahonavis could probably fly but would have been more clumsy in the air than modern birds.

Another species of dromaeosaurid, Microraptor gui, may have been capable of gliding using its well-developed wings on both the fore and hind limbs. A 2005 study by Sankar Chatterjee suggested that the wings of Microraptor functioned like a split-level "biplane", and that it likely employed a phugoid style of gliding, in which it would launch from a perch and swoop downward in a U-shaped curve, then lift again to land on another tree, with the tail and hind wings helping to control its position and speed. Chatterjee also found that Microraptor had the basic requirements to sustain level powered flight in addition to gliding.

Changyuraptor yangi is a close relative of Microraptor gui, also thought to be a glider or flyer based on the presence of four wings and similar limb proportions. However, it is a considerably larger animal, around the size of a wild turkey, being among the largest known flying Mesozoic paravians.

Another dromaeosaurid species, Deinonychus antirrhopus, may display partial flight capacities. The young of this species bore longer arms and more robust pectoral girdles than adults, and which were similar to those seen in other flapping theropods, implying that they may have been capable of flight when young and then lost the ability as they grew.

The possibility that Sinornithosaurus millenii was capable of gliding or even powered flight has also been brought up several times, though no further studies have occurred.

Zhenyuanlong preserves wing feathers that are aerodynamically shaped, with particularly bird-like coverts as opposed to the longer, wider-spanning coverts of forms like Archaeopteryx and Anchiornis, as well as fused sternal plates. Due to its size and short arms it is unlikely that Zhenyuanlong was capable of powered flight (though the importance of biomechanical modelling in this regard is stressed), but it may suggest a relatively close descendance from flying ancestors, or even some capacity for gliding or wing-assisted incline running.

### Paleopathology

In 2001, Bruce Rothschild and others published a study examining evidence for stress fractures and tendon avulsions in theropod dinosaurs and the implications for their behavior. Since stress fractures are caused by repeated trauma rather than singular events they are more likely to be caused by regular behavior than other types of injuries. The researchers found lesions like those caused by stress fractures on a dromaeosaurid hand claw, one of only two such claw lesions discovered in the course of the study. Stress fractures in the hands have special behavioral significance compared to those found in the feet, since stress fractures in the feet can be obtained while running or during migration. Hand injuries, by contrast, are more likely to be obtained while in contact with struggling prey.

### Swimming

At least one dromaeosaurid group, Halszkaraptorinae, whose members are halszkaraptorines, are most likely to have been specialised for aquatic or semiaquatic habits, having developed limb proportions, tooth morphology, and rib cage akin to those of diving birds.

Fishing habits have been proposed for unenlagiines, including comparisons to attributed semi-aquatic spinosaurids, but any aquatic propulsion mechanisms have not been discussed so far.

### Reproduction

In 2006, Grellet-Tinner and Makovicky reported an egg associated with a specimen of Deinonychus. The egg shares similarities with oviraptorid eggs, and the authors interpreted the association as potentially indicative of brooding. A study published in November 2018 by Norell, Yang and Wiemann et al., indicates that Deinonychus laid blue eggs, likely to camouflage them as well as creating open nests. Other dromaeosaurids may have done the same, and it is theorized that they and other maniraptoran dinosaurs may have been an origin point for laying colored eggs and creating open nests as many birds do today.

## In popular culture

Velociraptor, a dromaeosaurid, gained much attention after it was featured prominently in the 1993 Steven Spielberg film Jurassic Park. However, the dimensions of the Velociraptor in the film are much larger than the largest members of that genus. Robert Bakker recalled that Spielberg had been disappointed with the dimensions of Velociraptor and so upsized it. Gregory S. Paul, in his 1988 book Predatory Dinosaurs of the World, also considered Deinonychus antirrhopus a species of Velociraptor, and so rechristened the species Velociraptor antirrhopus''. This taxonomic opinion has not been widely followed.

## Timeline of dromaeosaurid genera

## See also

- Timeline of dromaeosaurid research
- Avialae

[^1]: Norell, M. Clark, J.M., Makovicky, P.J. (2001). "Phylogenetic relationships among coelurosaurian theropods. " New Perspectives on the Origin and Evolution of Birds: Proceedings of the International Symposium in Honor of John H. Ostrom", Yale Peabody Museum: 49–67

Family of feathered theropod dinosaurs


Battle of the Santa Cruz Islands

The Battle of the Santa Cruz Islands, fought during 25–27 October 1942, sometimes referred to as the Battle of Santa Cruz or Third Battle of Solomon Sea, in Japan as the Battle of the South Pacific (Japanese: 南太平洋海戦 Minamitaiheiyō kaisen), was the fourth aircraft carrier battle of the Pacific campaign of World War II. It was also the fourth major naval engagement fought between the United States Navy and the Imperial Japanese Navy during the lengthy and strategically important Guadalcanal campaign. As in the battles of the Coral Sea, Midway, and the Eastern Solomons, the ships of the two adversaries were rarely in sight or gun range of each other. Instead, almost all attacks by both sides were mounted by carrier- or land-based aircraft.

In an attempt to drive Allied forces from Guadalcanal and nearby islands and end the stalemate that had existed since September 1942, the Imperial Japanese Army planned a major ground offensive on Guadalcanal for 20–25 October 1942. In support of this offensive, and with the hope of engaging Allied naval forces, Japanese carriers and other large warships moved into a position near the southern Solomon Islands. From this location, the Japanese naval forces hoped to engage and decisively defeat any Allied (primarily U.S.) naval forces, especially carrier forces, that responded to the ground offensive. Allied naval forces also hoped to meet the Japanese naval forces in battle, with the same objectives of breaking the stalemate and decisively defeating their adversary.

The Japanese ground offensive on Guadalcanal was underway with the Battle for Henderson Field while the naval warships and aircraft from the two adversaries confronted each other on the morning of 26 October 1942, just north of the Santa Cruz Islands. After an exchange of carrier air attacks, Allied surface ships retreated from the battle area with the fleet carrier Hornet sunk, and another fleet carrier, Enterprise, heavily damaged. The participating Japanese carrier forces also retired because of high aircraft and aircrew losses, plus significant damage to the fleet carrier Shōkaku and the light carrier Zuihō.

Santa Cruz was a tactical victory and a short-term strategic victory for the Japanese in terms of ships sunk and damaged, and control of the seas around Guadalcanal. However, Japan's loss of many irreplaceable veteran aircrews proved to be a long-term strategic advantage for the Allies, whose aircrew losses in the battle were relatively low and quickly replaced. The Japanese had hoped for and needed a bigger, more decisive victory. The fact that the naval battle was won just after the land battle was lost meant that the opportunity to exploit their victory in the battle had already passed.

## Background

On 8 August 1942, Allied forces, predominantly from the United States, landed on Japanese-occupied Guadalcanal, Tulagi, and the Florida Islands in the Solomon Islands. The landings on the islands were meant to deny their use by the Japanese as bases for threatening the supply routes between the U.S. and Australia, and to secure the islands as starting points for a campaign with the eventual goal of neutralizing the major Japanese base at Rabaul while also supporting the Allied New Guinea campaign. The landings initiated the six-month-long Guadalcanal campaign.

After the Battle of the Eastern Solomons on 24–25 August, in which the fleet carrier USS Enterprise was heavily damaged and forced to sail to Pearl Harbor, Hawaii, for a month of major repairs, three U.S. carrier task forces remained in the South Pacific area. The task forces were based around the fleet carriers USS Wasp, Saratoga, and Hornet plus their respective air groups and supporting surface warships, including battleships, cruisers, and destroyers, and were primarily stationed between the Solomons and New Hebrides (Vanuatu) islands. In this area of operations, the carriers were charged with guarding the line of communication between the major Allied bases at New Caledonia and Espiritu Santo, supporting the Allied ground forces at Guadalcanal and Tulagi against any Japanese counteroffensives, covering the movement of supply ships to Guadalcanal, and engaging and destroying any Japanese warships, especially carriers, that came within range. The area of ocean in which the U.S. carrier task forces operated was known as "Torpedo Junction" by U.S. forces because of the high concentration of Japanese submarines in the area.

On 31 August, Saratoga was torpedoed by Japanese submarine I-26 and was out of action for three months for repairs. On 15 September, Wasp was hit by three torpedoes fired by Japanese submarine I-19 while supporting a major reinforcement and resupply convoy to Guadalcanal and almost engaging the Japanese carriers Shōkaku and Zuikaku, which withdrew just before the two adversaries came into range of each other's aircraft. With power knocked out from torpedo damage, Wasp's damage-control teams were unable to contain the ensuing large fires, and she was abandoned and scuttled.

Although the U.S. now had only one operational carrier, Hornet, in the South Pacific, the Allies still maintained air superiority over the southern Solomon Islands because of their aircraft based at Henderson Field on Guadalcanal. However, at night, when aircraft were not able to operate effectively, the Japanese were able to operate their ships around Guadalcanal almost at will. Thus, a stalemate in the battle for Guadalcanal developed—the Allies delivered supplies and reinforcements to Guadalcanal during the day, and the Japanese did the same by warship, referred to as the "Tokyo Express" by the Allies, at night—with neither side able to deliver enough troops to the island to secure a decisive advantage. By mid-October, both sides had roughly an equal number of troops on the island. The stalemate was briefly interrupted by two large-ship naval actions. On the night of 11–12 October, a U.S. naval force intercepted and defeated a Japanese naval force en route to bombard Henderson Field in the Battle of Cape Esperance. But just two nights later, a Japanese force that included the battleships Haruna and Kongō successfully bombarded Henderson Field, destroying most of the U.S. aircraft there and inflicting severe damage on the field's facilities.

The U.S. made two moves to try to break the stalemate in the battle for Guadalcanal. First, repairs to Enterprise were expedited so that she could return to the South Pacific as soon as possible. On 10 October, Enterprise received her new air group (Air Group 10) and on 16 October, she left Pearl Harbor; and on 23 October, she arrived back in the South Pacific and rendezvoused with Hornet and the rest of the Allied South Pacific naval forces on 24 October, 273 nmi (506 km; 314 mi) northeast of Espiritu Santo.

Second, on 18 October, Admiral Chester Nimitz, Allied Commander-in-Chief of Pacific Forces, replaced Vice Admiral Robert L. Ghormley with Vice Admiral William Halsey, Jr. as Commander, South Pacific Area: this position commanded Allied forces involved in the Solomon Islands campaign. Nimitz felt that Ghormley had become too myopic and pessimistic to lead Allied forces effectively in the struggle for Guadalcanal. Halsey was reportedly respected throughout the U.S. naval fleet as a "fighter". Upon assuming command, Halsey immediately began making plans to draw the Japanese naval forces into a battle, writing to Nimitz, "I had to begin throwing punches almost immediately."

The Japanese Combined Fleet was also seeking to draw Allied naval forces into what was hoped to be a decisive battle. Two fleet carriers—Hiyō and Jun'yō, as well as the light carrier Zuihō—arrived at the main Japanese naval base at Truk Atoll from Japan in early October and joined Shōkaku and Zuikaku. With five carriers fully equipped with air groups, plus their numerous battleships, cruisers, and destroyers, the Japanese Combined Fleet, directed by Admiral Isoroku Yamamoto, was confident that it could make up for the defeat at the Battle of Midway. Apart from a couple of air raids on Henderson Field in October, the Japanese carriers and their supporting warships stayed in the northwestern area of the Solomon Islands, out of the battle for Guadalcanal and waiting for a chance to approach and engage the U.S. carriers. With the Japanese Army's next planned major ground attack on Allied forces on Guadalcanal set for 20 October, Yamamoto's warships began to move towards the southern Solomons to support the offensive and to be ready to engage any enemy ships, especially carriers, that approached to support the Allied defenses on Guadalcanal.

## Prelude

On or around 11 October a large force consisting of aircraft carriers, battleships, and their escorts departed Truk for an extended sortie in support of an October Guadalcanal offensive. On the same day a major reinforcement convoy reached Guadalcanal, but a force of supporting heavy cruisers was prevented from bombarding Henderson Field and turned back in what became known as the Battle of Cape Esperance. What followed were three heavy bombardment missions conducted by battleships and heavy cruisers between 13 October and 16 October (this was the heaviest naval attack on the airfield in the entire campaign), the first and third of those conducted by vessels detached from Vice admiral Nobutake Kondō's Advance Force. Starting midnight on 14 October, another major convoy consisting of four transports unloaded the bulk of their cargo successfully, including tanks and heavy artillery. On 15 October, the destroyer Meredith, while escorting the tug Vireo pulling a resupply barge, was spotted and sunk by aircraft from Zuikaku and Shokaku. On 17 October, Hiyō and Jun'yō launched a strike force to attack transports off Lunga Point, but caused no damage. The large body of warships would remain in the waters around Guadalcanal until after fighting in the Battle of the Santa Cruz Islands had ceased and returned to Truk at the end of October. The recently commissioned carrier Hiyō was originally part of the fleet, but a fire in her engineering room on 21 October forced her to retire to Truk for repairs. On 25 October, 6 bombers and 12 fighters from Jun'yo attacked Henderson Field, but did little damage.

From 20 to 25 October, Japanese land forces on Guadalcanal attempted to capture Henderson Field with a large-scale attack against the U.S. defenders. The attack was decisively defeated with heavy casualties for the Japanese. Incorrectly believing that the Japanese army troops had succeeded in capturing Henderson Field, the Japanese sent warships from the Shortland Islands toward Guadalcanal on the morning of 25 October to support their ground forces on the island. Aircraft from Henderson Field attacked the convoy throughout the day, sinking the light cruiser Yura (with some help from B-17s out of Espiritu Santo) and damaging the destroyer Akizuki.

Despite the failure of the Japanese ground offensive and the loss of Yura, the rest of the Combined Fleet continued to maneuver near the southern Solomon Islands on 25 October in the hope of engaging Allied naval forces in a battle. The Japanese naval forces now comprised four carriers (two large, one medium, one light), Hiyō having departed, with a combined aircraft complement of approximately three Shokaku-class fleet carriers.

The Japanese naval forces were divided into three groups: the "Advanced" force of Jun'yō, four heavy cruisers, one light cruiser, and seven destroyers commanded by Kondō in heavy cruiser Atago with a support group consisting of two battleships and two destroyers under the command of Rear Admiral Takeo Kurita; the "Main Body" of Shōkaku, Zuikaku, and Zuihō plus one heavy cruiser and eight destroyers, commanded by Vice Admiral Chūichi Nagumo aboard Shōkaku; and the "Vanguard" force of two battleships, three heavy cruisers, one light cruiser, and seven destroyers, commanded by Rear Admiral Hiroaki Abe in the battleship Hiei. In addition to commanding the Advanced force, Kondo acted as the overall commander of the three forces.

On the U.S. side, the Hornet and Enterprise task groups, under the overall command of Rear Admiral Thomas Kinkaid, swept around to the north of the Santa Cruz Islands on 25 October, searching for the Japanese naval forces. The U.S. warships were deployed as two separate carrier groups, separated from each other by about 10 nmi (19 km; 12 mi). A U.S. PBY Catalina reconnaissance seaplane based in the Santa Cruz Islands located the Japanese Main Body carriers at 11:03. However, the Japanese carriers were about 355 nmi (657 km; 409 mi) from the U.S. force, just beyond carrier aircraft range. Kinkaid, hoping to close the range to be able to execute an attack that day, steamed towards the Japanese carriers at top speed and, at 14:25, launched a strike force of 23 aircraft. But the Japanese, knowing that they had been spotted by U.S. aircraft and not knowing where the U.S. carriers were, turned to the north to stay out of range of the U.S. carriers' aircraft. Thus, the U.S. strike force returned to its carriers without finding or attacking the Japanese warships.

## Battle

### Carrier action on 26 October: first strikes

At 02:50 on 26 October, the Japanese naval forces reversed direction and the naval forces of the two adversaries closed the distance until they were only 200 nmi (370 km; 230 mi) away from each other by 05:00. Both sides launched search aircraft and prepared their remaining aircraft to attack as soon as the other side's ships were located. Although a radar-equipped Catalina sighted the Japanese carriers at 03:10, the report did not reach Kinkaid until 05:12. Therefore, believing that the Japanese ships had probably changed position during the intervening two hours, he decided to withhold launching a strike force until he received more current information on the location of the Japanese ships.

At 06:45, a U.S. scout aircraft sighted the carriers of Nagumo's main body. At 06:58, a Japanese scout aircraft reported the location of Hornet's task force. Both sides raced to be the first to attack the other. The Japanese were first to get their strike force launched, with 64 aircraft, including 21 Aichi D3A2 dive bombers, 20 Nakajima B5N2 torpedo bombers, 21 A6M3 Zero fighters, and 2 Nakajima B5N2 contact aircraft on the way towards Hornet by 07:40. This first strike was commanded by Lieutenant Commander Shigeharu Murata, while the fighter cover was led by Lieutenants Ayao Shirane and Saneyasu Hidaka. Also at 07:40, two U.S. SBD-3 Dauntless scout aircraft, responding to the earlier sighting of the Japanese carriers, arrived and dove on Zuihō. With the Japanese combat air patrol (CAP) busy chasing other U.S. scout aircraft away, the two U.S. aircraft were able to hit Zuihō with both their 500-pound bombs, causing heavy damage and preventing the carrier's flight deck from being able to land aircraft.

Meanwhile, Kondo ordered Abe's Vanguard force to race ahead to try to intercept and engage the U.S. warships. Kondo also brought his own Advanced force forward at flank speed so that Jun'yō's aircraft could join in the attacks on the U.S. ships. At 08:10, Shōkaku launched a second wave of strike aircraft, consisting of 19 dive bombers and five Zeros, and Zuikaku launched 16 torpedo bombers and 4 Zeros at 08:40. The second strike leader was Lieutenant Commander Mamoru Seki, while the fighter cover was led by Lieutenant Hideki Shingo. Thus, by 09:10 the Japanese had over 100 aircraft on the way to attack the U.S. carriers.

The U.S. strike aircraft were running about 20 minutes behind the Japanese. Believing that a speedy attack was more important than a massed attack, and because they lacked fuel to spend time assembling prior to the strike, the U.S. aircraft proceeded in small groups towards the Japanese ships, rather than forming into a single large strike force. The first group—consisting of 15 Douglas SBD Dauntless dive bombers, 6 Grumman TBF-1 Avenger torpedo bombers, and eight Grumman F4F Wildcat fighters, led by Lieutenant Commander William J. "Gus" Widhelm from Hornet—was on its way by about 08:00. A second group—consisting of three SBDs, nine TBFs (including the Air Group Commander's), and eight Wildcats from Enterprise—was off by 08:10. A third group—consisting of nine SBDs, ten TBFs (including the Air Group Commander's), and seven F4Fs from Hornet—was on its way by 08:20.

At 08:40, the opposing aircraft strike formations passed within sight of each other. Lieutenant Hidaka's nine Zuihō Zeros surprised and attacked the Enterprise group, attacking the climbing aircraft from out of the sun. In the resulting engagement, four Zeros, three Wildcats, and two TBFs were shot down, with another two TBFs and a Wildcat forced to return to Enterprise with heavy damage. The remaining Zuihō Zeros, having exhausted their ammunition, withdrew from the action.

At 08:50, the lead U.S. attack formation from Hornet spotted four ships from Abe's Vanguard force. Pressing on, the U.S. aircraft sighted the Japanese carriers and prepared to attack. Three Zeros from Zuihō attacked the formation's Wildcats, drawing them away from the bombers they were assigned to protect. Thus, the dive bombers in the first group initiated their attacks without fighter escort. Twelve Zeros from the Japanese carrier CAP attacked the SBD formation, shot down two (including Widhelm's, though he survived), and forced two more to abort. The remaining 11 SBDs commenced their attack dives on Shōkaku at 09:27, hitting her with three to six bombs, wrecking her flight deck, and causing serious damage to the interior of the ship. The final SBD of the 11 lost track of Shōkaku and instead dropped its bomb near the Japanese destroyer Teruzuki, causing minor damage. The six TBFs in the first strike force, having become separated from their strike group, did not find the Japanese carriers and eventually turned back towards Hornet. On the way back, they attacked the Japanese heavy cruiser Tone, missing with all their torpedoes.

The TBFs of the second U.S. attack formation from Enterprise were unable to locate the Japanese carriers and instead attacked the Japanese heavy cruiser Suzuya from Abe's Vanguard force but caused no damage. At about the same time, nine SBDs from the third U.S. attack formation—from Hornet—found Abe's ships and attacked the Japanese heavy cruiser Chikuma, hitting her with two 1,000 lb (450 kg) bombs and causing heavy damage. The three Enterprise SBDs then arrived and also attacked Chikuma, causing more damage with one bomb hit and two near-misses. Finally, the nine TBFs from the third strike group arrived and attacked the smoking Chikuma, scoring one more hit. Chikuma, escorted by two destroyers, withdrew from the battle and headed towards Truk for repairs.

The U.S. carrier forces received word from their outbound strike aircraft at 08:30 that Japanese attack aircraft were headed their way. At 08:52, the Japanese strike force commander sighted the Hornet task force—the Enterprise task force was hidden by a rain squall—and deployed his aircraft for attack. At 08:55, the U.S. carriers detected the approaching Japanese aircraft on radar—about 35 nmi (65 km; 40 mi) away—and began to vector the 37 Wildcats of their CAP to engage the incoming Japanese aircraft. However, communication problems, mistakes by the U.S. fighter control directors, and primitive control procedures prevented all but a few of the Wildcats from engaging the Japanese aircraft before they began their attacks on Hornet. Although the U.S. CAP, including fighter pilot Swede Vejtasa, was able to shoot down or damage several dive bombers (the formation leader Lieutenant Sadamu Takahashi had to abort the dive due to the damage), most of the Japanese aircraft commenced their attacks relatively unmolested by U.S. fighters.

At 09:09, the anti-aircraft guns of Hornet and her escorting warships opened fire as the 20 untouched Japanese torpedo planes and remaining 16 dive bombers commenced their attacks on the carrier. At 09:12, a dive bomber placed its 250 kg semi-armor-piercing "ordinary" bomb dead center on Hornet's flight deck, across from the island, which penetrated three decks before exploding, killing 60 men. Moments later, a 242 kg high-explosive "land" bomb struck the flight deck, detonating on impact to create an 11 ft (3.4 m) hole and kill 30 men. A minute or so later, a third bomb hit Hornet near where the first bomb hit, penetrating three decks before exploding, causing severe damage but no loss of life. At 09:14, a dive bomber was set on fire by Hornet's anti-aircraft guns; the pilot, Warrant Officer Shigeyuki Sato, deliberately crashed into Hornet's stack, killing seven men and spreading burning aviation fuel over the signal deck.

At the same time as the dive bombers were attacking, the 20 torpedo bombers were also approaching Hornet from two different directions. Despite suffering heavy losses from anti-aircraft fire, including Murata, the torpedo planes planted two torpedoes in Hornet's side between 09:13 and 09:17, knocking out her engines. As Hornet came to a stop, a damaged Japanese dive bomber approached and purposely crashed into the carrier's side, starting a fire near the ship's main supply of aviation fuel. At 09:20, the surviving Japanese aircraft departed, leaving Hornet dead in the water and burning. Twenty-five Japanese and six American aircraft were destroyed in this attack, including 12 dive bombers, ten torpedo planes and at least one Zero.

With the assistance of fire hoses from three escorting destroyers, the fires on Hornet were under control by 10:00. Wounded personnel were evacuated from the carrier, and an attempt was made by the heavy cruiser USS Northampton under Captain Willard A. Kitts to tow Hornet away from the battle area. However, the effort to rig the towline took some time, and more attack waves of Japanese aircraft were inbound.

### Carrier action on 26 October: post-first strike actions

Starting at 09:30, Enterprise landed many of the damaged and fuel-depleted CAP fighters and returning scout aircraft from both carriers. However, with her flight deck full, and the second wave of incoming Japanese aircraft detected on radar at 09:30, Enterprise ceased landing operations at 10:00. Fuel-depleted aircraft then began ditching in the ocean, and the carrier's escorting destroyers rescued the aircrews. One of the ditching aircraft, a damaged TBF from Enterprise's strike force that had been attacked earlier by Zeros from Zuihō, crashed into the water near the destroyer USS Porter. As Porter rescued the TBF's aircrew, she was struck by a torpedo, possibly from the ditched aircraft, causing heavy damage and killing 15 crewmen. After the task force commander ordered the destroyer scuttled, the crew was rescued by the destroyer USS Shaw which then sank Porter with gunfire ().

As the first wave of Japanese strike aircraft began returning to their carriers from their attack on Hornet, one of them spotted the Enterprise task force, which had now emerged from the rain squall, and reported the carrier's position. The second Japanese aircraft strike wave, believing Hornet to be sinking, directed their attacks on the Enterprise task force, beginning at 10:08. Again, the U.S. CAP had trouble intercepting the Japanese aircraft before they attacked Enterprise, shooting down only 2 of the 19 dive bombers as they began their dives on the carrier. Attacking through the intense anti-aircraft fire put up by Enterprise and her escorting warships, Seki's division attacked first and scored no hits. Next attacked the division led by Lieutenant Keiichi Arima that scored hits on the carrier with two 250 kg semi-AP "ordinary" bombs, where the first one was released by Arima's pilot, Petty Officer Kiyoto Furuta. The 2 bombs killed 44 men and wounded 75, and caused heavy damage to the carrier, including jamming her forward elevator in the "up" position. In addition, Arima's division also achieved a near-miss with another bomb. However, ten of the nineteen Japanese bombers were lost in this attack, including Seki's, with two more ditching on their return.

Twenty minutes later, the 16 Zuikaku torpedo planes arrived and split up to attack Enterprise. One group of torpedo bombers was attacked by two CAP Wildcats, again including Vejtasa, which shot down three of them and damaged a fourth. On fire, the fourth damaged aircraft purposely crashed into the destroyer Smith, setting the ship on fire and killing 57 of her crew. The torpedo carried by this aircraft detonated shortly after impact, causing more damage. The fires initially seemed out of control until Smith's commanding officer ordered the destroyer to steer into the large spraying wake of the battleship USS South Dakota, which helped put out the fires. Smith then resumed her station, firing her remaining anti-aircraft guns at the torpedo planes.

The remaining torpedo planes attacked Enterprise, South Dakota, and the cruiser Portland, but all of their torpedoes missed or failed, causing no damage. The engagement was over at 10:53; 9 of the 16 torpedo aircraft were lost in this attack. After suppressing most of the onboard fires, at 11:15 Enterprise reopened her flight deck to begin landing returning aircraft from the morning U.S. strikes on the Japanese warship forces. However, only a few aircraft landed before the next wave of Japanese strike aircraft arrived and began their attacks on Enterprise, forcing a suspension of landing operations.

Between 09:05 and 09:14, Jun'yō had arrived within 280 nmi (320 mi; 520 km) of the U.S. carriers and launched a strike of 17 dive bombers and 12 Zeros, under the command of Lieutenant Yoshio Shiga. As the Japanese main body and advanced force maneuvered to try to join formations, Jun'yō readied follow-up strikes. At 11:21, the Jun'yō aircraft arrived and dove on the Enterprise task force. The dive bombers scored one near miss on Enterprise, causing more damage, and one hit each on South Dakota and light cruiser San Juan, causing moderate damage to both ships. Eight of the seventeen Japanese dive bombers were destroyed in this attack, with three more ditching on their return.

At 11:35, with Hornet out of action, Enterprise heavily damaged, and the Japanese assumed to have one or two undamaged carriers in the area, Kinkaid decided to withdraw Enterprise and her screening ships from the battle. Leaving Hornet behind, Kinkaid directed the carrier and her task force to retreat as soon as they were able. Between 11:39 and 13:22, Enterprise recovered 57 of the 73 airborne U.S. aircraft as she retreated. The remaining U.S. aircraft ditched in the ocean, and their aircrews were rescued by escorting warships.

Between 11:40 and 14:00, the two undamaged Japanese carriers, Zuikaku and Jun'yō, recovered the few aircraft that returned from the morning strikes on Hornet and Enterprise and prepared follow-up strikes. It was now that the devastating losses sustained during these attacks became apparent. Lt. Cmdr. Masatake Okumiya, Jun'yō's air staff officer, described the return of the carrier's first strike groups:

> We searched the sky with apprehension. There were only a few planes in the air in comparison with the numbers launched several hours before... The planes lurched and staggered onto the deck, every single fighter and bomber bullet holed ... As the pilots climbed wearily from their cramped cockpits, they told of unbelievable opposition, of skies choked with antiaircraft shell bursts and tracers.

Only one of Jun'yō's bomber leaders returned from the first strike, and upon landing he appeared "so shaken that at times he could not speak coherently".

At 13:00, Kondo's Advanced force and Abe's Vanguard force warships together headed directly towards the last reported position of the U.S. carrier task forces and increased speed to try to intercept them for a gun battle. The damaged carriers Zuihō and Shōkaku, with Nagumo still on board, retreated from the battle area, leaving Rear Admiral Kakuji Kakuta in charge of the Zuikaku and Jun'yō aircraft forces. At 13:06, Jun'yō launched her second strike of seven torpedo planes led by Lieutenant Yoshiaki Irikiin, which were escorted by eight Zeros led by Lieutenant Shirane. At the same time, Zuikaku launched her third strike of seven torpedo planes, two dive bombers, and five Zeros, under the command of Lieutenant (jg) Ichirō Tanaka. Most of the torpedo planes were armed with an 800 kg armor-piercing bomb. At 15:35, Jun'yō launched the last Japanese strike force of the day, consisting of four dive bombers and six Zeros, again under the command of Lieutenant Shiga.

After several technical problems, Northampton finally began slowly towing Hornet out of the battle area at 14:45, at a speed of only five knots. Hornet's crew was on the verge of restoring partial power, but at 15:20, Jun'yō's second strike arrived, and the seven torpedo planes attacked the almost stationary carrier. Although six of the torpedo planes missed, at 15:23, one torpedo struck Hornet amidships, which proved to be the fatal blow. The torpedo hit destroyed the repairs to the power system and caused heavy flooding and a 14-degree list. With no power to pump out the water, Hornet was given up for lost, and the crew abandoned ship. The third strike from Zuikaku attacked Hornet during this time, where B5N level bombers hit the sinking ship with one 800 kg bomb. All of Hornet's crewmen were off by 16:27. During the last Japanese attack of the day, a dive bomber from Jun'yō's third strike dropped one more 250 kg semi-AP bomb on the sinking carrier at 17:20.

After being informed that Japanese forces were approaching and that further towing efforts were infeasible, Halsey ordered Hornet sunk. While the rest of the U.S. warships retired towards the southeast to get out of range of Kondō's and Abe's oncoming fleet, the destroyers USS Mustin and Anderson attempted to scuttle Hornet with multiple torpedoes and over 400 shells, but she still remained afloat. With advancing Japanese naval forces only 20 minutes away, the two U.S. destroyers abandoned Hornet's burning hulk at 20:40. By 22:20, the rest of Kondō's and Abe's warships had arrived at Hornet's location. The destroyers Makigumo and Akigumo then finished Hornet with four 24 in (610 mm) torpedoes. At 01:35 on 27 October 1942, she finally sank, at approximately . Several night attacks by radar-equipped Catalinas on Jun'yō and Teruzuki, knowledge of the head start the U.S. warships had in their retreat from the area, plus a critical fuel situation apparently caused the Japanese to reconsider further pursuit of the U.S. warships. After refueling near the northern Solomon Islands, the Japanese ships returned to their main base at Truk on 30 October. During the U.S. withdrawal from the battle area towards Espiritu Santo and New Caledonia, while taking evasive action from a Japanese submarine, South Dakota collided with the destroyer Mahan, heavily damaging Mahan.

## Aftermath

Both sides claimed victory. The Americans stated that two Shōkaku-class fleet carriers had been hit with bombs and eliminated. Kinkaid's summary of damage to the Japanese included hits to a battleship, three heavy cruisers, and a light cruiser, and possible hits on another heavy cruiser. In reality, Shōkaku, Zuihō, and Chikuma were the only ships hit during the battle, none of which sank. For their part, the Japanese asserted that they sank three American carriers, one battleship, one cruiser, one destroyer, and one "unidentified large warship". Actual American losses comprised the carrier Hornet and the destroyer Porter, and damage to Enterprise, the light cruiser San Juan, the destroyer Smith and the battleship South Dakota.

The loss of Hornet was a severe blow for Allied forces in the South Pacific, leaving Enterprise and Saratoga as the only operational Allied carriers in the entire Pacific theater. As Enterprise retreated from the battle, the crew posted a sign on the flight deck: "Enterprise vs Japan". Enterprise received temporary repairs at New Caledonia and, although not fully restored, returned to the southern Solomons area just two weeks later to support Allied forces during the Naval Battle of Guadalcanal. There she played an important role in what turned out to be the decisive naval engagement in the overall campaign for Guadalcanal when her aircraft sank several Japanese warships and troop transports during the naval skirmishes around Henderson Field. The lack of carriers pressed the Americans and Japanese to deploy battleships in night operations around Guadalcanal, one of only two actions in the entire Pacific War in which battleships fought each other, with South Dakota again being damaged while two Japanese battleships were lost.

Although the Battle of Santa Cruz was a tactical victory for the Japanese in terms of ships sunk, it came at a high cost for their naval forces, as Jun'yō was the only active aircraft carrier left to challenge Enterprise or Henderson Field for the remainder of the Guadalcanal campaign. Zuikaku, despite being undamaged and having recovered the aircraft from the two damaged carriers, returned to home islands via Truk for training and aircraft ferrying duties, returning to the South Pacific only in February 1943 to cover the evacuation of Japanese ground forces from Guadalcanal. Both damaged carriers were forced to return to Japan for extensive repairs and refitting. After repair, Zuihō returned to Truk in late January 1943. Shōkaku was under repair until March 1943 and did not return to the front until July 1943, when she was reunited with Zuikaku at Truk.

The most significant losses for the Japanese Navy were in aircrew. The U.S. lost 81 of the 175 aircraft that were available at the start of the battle; of these, 33 were fighters, 28 were dive-bombers, and 20 were torpedo bombers. However, only 26 pilots and aircrew members were lost. The Japanese fared much worse, especially in airmen; in addition to losing 99 aircraft of the 203 involved in the battle, they lost 148 pilots and aircrew members, including two dive bomber group leaders, three torpedo squadron leaders, and eighteen other section or flight leaders. The most notable casualties were the commanders of the first two strikes – Murata and Seki. Forty-nine percent of the Japanese torpedo bomber aircrews involved in the battle were killed, along with 39% of the dive bomber crews and 20% of the fighter pilots. The Japanese lost more aircrew at Santa Cruz than they had lost in each of the three previous carrier battles at Coral Sea (90), Midway (110), and Eastern Solomons (61). By the end of the Santa Cruz battle, at least 409 of the 765 elite Japanese carrier aviators who had participated in the attack on Pearl Harbor were dead. Having lost so many of its veteran carrier aircrew, and with no quick way to replace them—because of an institutionalized limited capacity in its naval aircrew training programs and an absence of trained reserves—the undamaged Zuikaku was also ordered to return to Japan. Jun'yo remained and provided air support during the Naval Battle of Guadalcanal, Zuikaku returned just in time to cover the withdrawal of the forces from Guadalcanal.

Admiral Nagumo was relieved of command shortly after the battle and reassigned to shore duty in Japan. He acknowledged that the victory was incomplete:

> [T]his battle was a tactical win, but a shattering strategic loss for Japan ... Considering the great superiority of our enemy's industrial capacity, we must win every battle overwhelmingly in order to win this war. This last one, although a victory, unfortunately, was not an overwhelming victory.

In retrospect, despite being a tactical victory, the battle effectively ended any hope the Japanese Navy might have had of scoring a decisive victory before the industrial might of the United States placed that goal out of reach. Historian Eric Hammel summed up the significance of the Battle of the Santa Cruz Islands as, "Santa Cruz was a Japanese victory. That victory cost Japan her last best hope to win the war."

Military historian Dr. John Prados offers a dissenting view, asserting that this was not a Pyrrhic victory for Japan, but a strategic victory:

> By any reasonable measure the Battle of Santa Cruz marked a Japanese victory—and a strategic one. At its end, the Imperial Navy possessed the only operational carrier force in the Pacific. The Japanese had sunk more ships and more combat tonnage, had more aircraft remaining, and were in physical possession of the battle zone... Arguments based on aircrew losses or who owned Guadalcanal are about something else—the campaign, not the battle.

In Prados' view, the real story of the aftermath is that the Imperial Navy failed to exploit their hard-won victory.

## See also

- Imperial Japanese Navy Air Service
- Imperial Japanese Navy in World War II
- United States Navy in World War II
- Pacific Theater aircraft carrier operations during World War II

### World War II carrier-versus-carrier engagements

- Battle of the Coral Sea
- Battle of Midway
- Battle of the Eastern Solomons
- Battle of the Philippine Sea
- Battle off Cape Engaño

Fourth carrier battle of the Pacific campaign of World War II

Battles and operations of World War II involving the Solomon Islands

Battles of World War II involving the United States

Military history of Japan during World War II

Naval battles of World War II involving Japan

Naval battles of World War II involving the United States

World War II aerial operations and battles of the Pacific theatre

World War II naval operations and battles of the Pacific theatre


Comeback (Glee)

"Comeback" is the thirteenth episode of the second season of the American musical television series Glee, and the thirty-fifth overall. It was written by series creator Ryan Murphy, directed by Bradley Buecker, and premiered on Fox on February 15, 2011. In the episode, glee club director Will Schuester (Matthew Morrison) allows cheerleading coach Sue Sylvester (Jane Lynch) to join the McKinley High glee club in an attempt to ease her depression. Club member Sam (Chord Overstreet) creates a tribute band to teen singer Justin Bieber in order to win the heart of Quinn (Dianna Agron), and is later joined by the group's other male members, minus co-captain Finn (Cory Monteith), to recreate Bieber's "Somebody to Love" and woo their significant others.

Prior to broadcast, Murphy dismissed rumors that "Comeback" would serve as a tribute to Bieber, and stated that such episodes are reserved for artists with extensive musical catalogs. "Comeback" was met with mixed reception from critics, who deemed it neither bad nor a standout. Critics such as Bobby Hankinson of the Houston Chronicle appreciated the episode's early Glee aesthetic. Amy Reiter of the Los Angeles Times felt that the episode lacked substance. Sue's storyline, which focuses on her depression and a suicide attempt with Flintstone gummies, was widely criticized for its inappropriateness. The other storylines had mixed to positive reviews, as many critics deemed the Bieber-related subplot the strongest. James Poniewozik of Time compared it favorably to the Madonna tribute episode "The Power of Madonna".

The episode features six musical performances, five of which were released as singles. Upon its initial airing, "Comeback" was watched by over 10.53 million US viewers, and acquired a 4.2/12 Nielsen rating/share in the 18–49 demographic. Unlike the story itself, most critics received the musical numbers with acclaim. The Glee take on Bieber's songs was praised, as were the vocals of cast members Amber Riley and Lea Michele in their duet of "Take Me or Leave Me" from Rent, and the confidence and performance of Ashley Fink in "I Know What Boys Like".

## Plot

After her cheerleading squad loses a competition for the first time in seven years, coach Sue Sylvester (Jane Lynch) becomes depressed, and stages an apparent suicide by "overdosing" on gummy vitamins. Her colleague, school guidance counselor Emma Pillsbury (Jayma Mays), suggests that she temporarily join the school glee club, New Directions, to lift her spirits. Hoping to create discord within the group, Sue pits members Mercedes (Amber Riley) and Rachel (Lea Michele) against one another. Her plan backfires when a duet between the two results in a deepening of their respect for one another vocally. In an attempt to bring out the good in Sue, club director Will Schuester (Matthew Morrison) takes her to a pediatric cancer ward, where they sing "This Little Light of Mine" with the patients.

Club member Sam Evans (Chord Overstreet) establishes a one-man tribute band to teen singer Justin Bieber, which he calls "The Justin Bieber Experience", in the hope of winning over his girlfriend Quinn (Dianna Agron), whom he suspects still has feelings for her ex-boyfriend Finn (Cory Monteith). Sam performs Bieber's "Baby" for the glee club, and dedicates it to Quinn; the performance also excites the other girls in the club. Several of the male members—Puck (Mark Salling), Artie (Kevin McHale) and Mike (Harry Shum Jr.)—are impressed by the effect he has on the girls, and convince him to let them join his tribute band. The foursome then perform "Somebody to Love", and recreate the music video for the song in the auditorium, which makes the girls go crazy. Quinn chooses Sam over Finn, but when Santana Lopez (Naya Rivera) convinces Sam that Quinn cheated on him, he breaks up with her and begins dating Santana.

Meanwhile, Lauren Zizes (Ashley Fink) enlists Puck to help her with her first glee club solo. With Puck's assistance, she performs "I Know What Boys Like" by The Waitresses, and using a trick he taught her, imagines the club members in their underwear for confidence. Later, Sue suggests that the club perform the anthem "Sing" by My Chemical Romance, as they must present an anthem at the forthcoming Regionals competition. They rehearse the song, and it is well received by most of the members, who disregard Rachel's suggestion that they should instead compose an original anthem. Her week with New Directions over, Sue reveals that she has become the vocal coach for one of the glee club's Regionals competitors, Aural Intensity.

## Production

In January 2011, rumors began to circulate that Glee was planning a Justin Bieber tribute episode, similar to "The Power of Madonna" for Madonna, and "Britney/Brittany" for Britney Spears. Series creator Ryan Murphy refuted the claims, and stated that such episodes are reserved for artists with extensive musical catalogs. He confirmed, however, that Bieber's music would be used in an episode in season two as a "small plot point", and Overstreet's Sam would perform a song by the artist for Quinn's approval. On the red carpet at the 68th Golden Globe Awards, cast member Riley confirmed to MTV News that Bieber's songs "Baby" and "Somebody to Love" would be featured in the upcoming episode, and the singer would receive a tribute similar to Lady Gaga in "Theatricality"—a tribute, but without a full episode devoted to his catalog. Via his official Facebook page, Bieber stated that he was "truly honoured" to have his music covered on Glee. Prior to broadcast, Overstreet and Bieber interacted via the social networking website Twitter, where Bieber told him "we just gotta work on those moves", and to "kill it!"

In addition to "Baby" and "Somebody to Love", the episode featured cover versions of "I Know What Boys Like" by The Waitresses performed by Fink, "Take Me or Leave Me" from Rent performed by Michele and Riley, "Sing" by My Chemical Romance, and an acoustic performance of the gospel children's song "This Little Light of Mine". The pediatric oncology scenes were filmed at the Children's Hospital Los Angeles' Center for Cancer and Blood Diseases, where eleven real patients performed alongside Morrison and Lynch. Bailey, the pediatric ward nurse, was played by guest-star Charlene Amoia, who had worked for the series' sound department during the first season. In June 2011, she deemed her "Comeback" appearance her favorite guest role in any series, due to working alongside the children, whom she was "so touched by". Amoia expanded: "They were the most vibrant, energetic kids. It was a really awesome storyline to be a part of. I was really moved by everything." Though she was not initially aware that the role would involve singing, Amoia was part of the "This Little Light of Mine" group number. The episode's recurring guest cast members were Overstreet as Sam, Iqbal Theba as Principal Figgins, Shum Jr. as Mike and Fink as Lauren.

## Reception

### Ratings

"Comeback" was watched by 10.53 million US viewers. It attained a 4.2/12 Nielsen rating/share in the 18–49 demographic, which made it the highest rated show of the night. It was the third most-watched scripted show of the week amongst adults aged 18–49, and placed 21st amongst all viewers. The episode declined by 9 percent and 1.12 million viewers on the previous episode, "Silly Love Songs".

With its Canadian broadcast, also on February 15, 2011, "Comeback" attained 1.75 million viewers and placed 18th in the weekly program rankings. It was again down on "Silly Love Songs", which ranked tenth and was watched by 2.08 million viewers. In Australia, where the episode aired on February 28, 2011, it was watched by 909,000 viewers and was the 11th most-viewed show of the night. Viewership was marginally down on the previous episode, which attracted 921,000 viewers and also placed 11th. In the UK, the episode was broadcast on April 4, 2011. It attained 2.57 million viewers—2.14 million on E4, and 427,000 on E4+1—and was the most-watched show on cable for the week. Viewership again declined slightly from the previous episode, which drew 2.63 million viewers.

### Critical response

The episode received mixed reviews from critics. Bobby Hankinson of the Houston Chronicle and E! Online's Jenna Mullins were pleased by how "Comeback" reminded them of early episodes of Glee—Mullins hailed the return of familiar characterization, and Hankinson commented: "It felt like old times, and it felt good." Though he observed that the episode was light on plot, Hankinson praised the writing and comedy. CNN's Lisa Respers France found the episode's title apt, as Glee was "firing on all cylinders" with little room for improvement. Erica Futterman of Rolling Stone was "pleasantly surprised", as she had anticipated a decline in quality from the previous episode, and Kevin Fallon of The Atlantic commented that apart from the Bieber jokes, "the rest of the episode was sharply written and loaded with self-referential jokes". Other critics found "Comeback" mediocre. Entertainment Weekly's Sandra Gonzalez wrote that it was "a bit off", The A.V. Club's Emily VanDerWerff felt that "something was missing, making the whole thing stultifying, lifeless, and boring", and Robert Canning of IGN deemed it "fine and inoffensive", but ultimately forgettable. Amy Reiter of the Los Angeles Times was "a little disappointed" in the episode for a lack of substance, creativity and emotional maturity. James Poniewozik of Time deemed it amongst his least favorite episodes, for "not even [being] bad in a memorable way". He noted that "Comeback" was "essentially a collection of subplots", and questioned its purpose.

The Sue storyline garnered many unfavorable reviews. Reiter criticized her inconsistent characterization, which made her actions seem "like fragments pasted together to form a disjointed collage". While VanDerWerff was more favorable, he wrote that Sue's jokes about committing "Sue-icide" were "neither dark enough to provoke a startled burst or laughter nor funny enough to overcome their central tastelessness", and called the scene in the pediatric oncology ward "woefully misjudged and inappropriately hilarious". The Atlantic's Meghan Brown found the use of seriously ill children "borderline offensive", and called Sue's suicide attempt "in totally bad taste". Miriam Krule of NPR felt that Glee treated suicide too lightly, and in doing so sent a mixed message to its youth audience. Poniewozik wrote that Sue has become "a burden on the show", and described her as "a breakout character who's broken out of the constraints of recognizable character". He questioned the point of her arc, and suggested that the attempt at humanizing her was redundant, as viewers already know Sue to be capable of compassion.

Other storylines received a more mixed response. Canning disliked the focus placed on Sam and his thin, "loveable dope" characterization. He found that the love-triangle plot made little sense, and as such was hard to invest in. In contrast, Poniewozik called Sam's Bieber subplot the episode's strongest element, and deemed it fun if inessential. He praised Glee for capturing the "disposable fun" of Bieber's music, "without either sneering at it or making it more than it is", and called it better in this respect than "The Power of Madonna". Lauren received several positive reviews. While VanDerWerff found her relationship with Puck "a lot less assured" than in "Silly Love Songs", Mullins and Gonzalez praised their "endearing" dynamic. Reiter felt that in "Comeback", while new characters like Sam and Lauren "managed to shine", established favorites fared less well: "Finn continues to be dismayingly drained of all that once made him so adorable, and Rachel, too, has been deprived of the depth and sex appeal she so carefully developed over time." Several critics raised similar criticism of Rachel—Gonzalez found her need for Brittany's help "too much of a regression", and disliked her return to "old, desperate habits" after several episodes of personal growth. Canning felt that the storyline was forced, and Poniewozik observed that the episode "seemed to be trying less to advance her character [than] simply to give her something to do." VanDerWerff wrote that Rachel appeared to have five different subplots, none of which came together cohesively, and that it reflected the awkward construction of the episode.

### Music and performances

The episode's musical covers and performances were mostly well received by critics. Hankinson wrote that the songs "blended all of the show's best charms", which he listed as "kitschy suprise [sic]", "slick production" and "raw vocal ability". Futterman also praised all of the music.

The Bieber numbers received a mostly positive reception. Mullins complimented them both, particularly Overstreet's performance of "Baby". Futterman said this performance was impressive, "a total pop star package that recalled the Biebs' swag". She found this element "smooth[ed] over" in "Somebody to Love", but called the recreation admirable nonetheless. Gonzalez highlighted the Bieber songs as the best of the episode; she gave "Baby" and "Somebody to Love" grades of "A" and "B+", respectively. On the former song, Gonzalez enjoyed Sam's performance, particularly his "übercorny dance moves that made [her] ache for the boy-band era." Although she complimented the male vocalists and their "almost perfect re-creation" of the video, Gonzalez was disappointed the show chose to repeat, rather than reinterpret, the choreography. Fallon praised the two songs: he called Sam "quite charming while channeling Bieber" and said "the acoustic opening to 'Baby' was actually very sweet, just as it was when Biebs stripped down the tune to open his Grammy performance". He added that the dancing "stood out" in "Somebody to Love". Raymund Flandez of The Wall Street Journal expressed disappointment in the Bieber performances "displayed so awkwardly and so undynamically" by Sam. On "Baby", he opined that Overstreet lacked "swagger", coordination and charm. He was more impressed by the rendition of "Somebody to Love", but noted that Sam was vocally overshadowed by Artie.

The performance of the duet "Take Me or Leave Me" elicited praise from Brown and Fallon, who both deemed it the highlight of the episode. Brown noted that "it had that addictive Glee quality of actually feeling like high school, and watching Mercedes and Rachel have a blast blasting each other was a treat." Gonzalez gave the duet a "B", as, while there was "so much to swoon for", she is more partial to ballads because they "discourage oversinging throughout the entire song". Futterman wrote that while Mercedes had more sass than Rachel, "both ladies sang". VanDerWerff did not see how the song was relevant, and felt that Michele's voice was ill-suited to it.

Flandez called Lauren's "I Know What Boys Like" the highlight of the episode, and VanDerWerff praised it as the best musical number. He complimented her confidence, but said the underwear joke was "unnecessary and overstated". In contrast, Gonzalez cited the underwear shots as a factor in raising her grade to a "C−" for a song without "basic musicality". Patrick Burns of The Atlantic was also unimpressed, and questioned Lauren's spot in glee club, as "her brazen character never ceases to please, but it's just not believable that she would join the glee club if she cannot sing." In December 2012, TV Guide named the cover one of Glee's worst performances.

On the New Directions collaboration with Sue on "Sing", Futterman wrote, "By turning down the rock and bringing in a choral element, the song actually came off as a great anthem for the bunch of misfits that is the New Directions. We kind of wish they had put on their choir robes instead and fully embraced the arrangement." Although Gonzalez gave the performance a "B", she called it "lacking" and not "regionals material": "We need to be blown away." TV Guide also listed this rendition as one of Glee's worst performances.

### Chart history

Of the five cover versions released as singles—the cover of "This Little Light of Mine" was not released—four debuted on the Billboard Hot 100, and appeared on other musical charts. These same four songs were also featured on the sixth soundtrack album of the series, Glee: The Music, Volume 5. On the Hot 100, the show's rendition of "Baby" debuted at number forty-seven; it was at number fifty-two on the Billboard Canadian Hot 100. The Glee cover version of "Sing" debuted on the Hot 100 at number forty-nine, placing higher than the original by My Chemical Romance, which climbed from number ninety-two to number fifty-eight, its best showing to that point; in Canada, both versions debuted on the Canadian Hot 100 in the same week, with the Glee version at number thirty-seven, the highest of the four Glee singles there, while the original charted twenty slots below it at number fifty-seven. The other two songs on the Hot 100 were "Take Me or Leave Me" at number fifty-one, which also made number sixty on the Canadian Hot 100, and "Somebody to Love" at number sixty-two, which also made number fifty-three on the Canadian Hot 100. "I Know What Boys Like" did not chart.

Television episodes written by Ryan Murphy (filmmaker)