Rapetosaurus

## RapetosaurusRapeto (Malagasy Deity) Lizard

 **Main** Segments

MainSegments

***“ Fifty foot-long Rapetosaurs. They have been attracted here by the promise of a mud bath. For Beelzebufo, their timing couldn't be much worse. ”***

― **David Attenborough**, *Swamps*
***Rapetosaurus*** (Rapeto Lizard, named after a giant deity in Malagasy folklore responsible for creating various features of the land) is a genus of titanosaurian sauropod dinosaur that lived in the Maevarano Formation, Madagascar, 70 - 66 million years ago, during the Maastrichtian stage of the Late Cretaceous Period.

## Description

Much like its Mongolian relative *Nemegtosaurus*, *Rapetosaurus* is a medium-sized titanosaur, merely 16.5 meters (54 feet) in length and around 10.3 metric tons (11.35 short tons) in weight. Prehistoric Planet brings up a weight of 70 metric tons (77 short tons), though given the animal's modest size, it unlikely weighed as much as a Mongolian Titan (which is stated to have the same weight in Deserts). Instead, this may be referring to the combined weight of all six individuals shown taking a mud bath, implying that each one weighs almost 12 metric tons (13.23 short tons).

Microscopic analysis and CT scans indicate that *Rapetosaurus* can grow quickly, around the same rate as an elephant, though it still would have taken them several years to reach adulthood, and several more to complete their lifespan should it not be prematurely ended. The fossil of a juvenile *Rapetosaurus*, estimated to have been 3.4 kilograms (8.8 pounds) when it hatched, grew to be around 40 kilograms (88 pounds) in a few weeks.

### Prehistoric Planet's Depiction

*Main: *Rapetosaurus* on Prehistoric Planet*

Main: *Rapetosaurus* on Prehistoric Planet

Prehistoric Planet depicts *Rapetosaurus* with an earthly brown color with a few streaks in a lighter shade. Osteoderms cover the animal's back, a feature based on evidence of such armor being found on other titanosaurs. Unlike some of the titanosaurs on Prehistoric Planet, *Rapetosaurus* is correctly depicted without thumb claws (for most - but not all - titanosaurs had specialized hands that lacked fingers).

A herd of six *Rapetosaurus* was featured in the third segment of Swamps, visiting a half-dry river bed to take a mud bath in it, disturbing the mating efforts of a male *Beelzebufo* in the process. As with all the sauropods that appeared in the first and second season (except for the Nemegt Forest Titanosaur), footage of *Rapetosaurus* is used in the Uncovered segment "How Did Dinosaurs Get So Big?"

## Habitat

*Main: Maevarano Formation*

Main: Maevarano Formation

***“ In Northern Madagascar, conditions are already changing. The first rain in months is reviving the parched land. As pools and channels refill, the animals return. ”***

― **David Attenborough**, *Swamps*
*Rapetosaurus* lived 70 - 66 million years ago in the Maevarano Formation in the Mahajanga Province of Madagascar. The Maevarano Formation is recognized as an alluvial plain where the discharge of rivers fluctuate. The area is also believed to have had reddish soil, with floodplains that supported vegetation able to grow in the relatively dry climate. The region, at times semi-arid (like it is today), at times undergoing strong dry and wet seasons, was eventually claimed by rising sea levels that pushed the shoreline back. This may or may not have been the result of the Cretaceous-Paleogene Extinction Event, a catastrophe that wiped out three-quarters of life on Earth.

## Behavior

### Social Habits

As with most sauropod depictions, Prehistoric Planet shows *Rapetosaurus* as a herding animal, albeit to a slightly lesser degree than other sauropods. The third segment of Swamps shows a small herd of six individuals traveling together. The herd likely only consists of adults, indicating that, like most sauropods, *Rapetosaurus* was an r-strategist, an animal that spawns many offsprings and provides them little or no parental care, with many expected to die while the fitter (or at least, luckier) ones surviving to adulthood to bring forth the next generation. Evidence of this can be seen via the remains of a 40-kilogram (88-pound) *Rapetosaurus*, which, based on bone remodeling, is believed to be capable of surviving on its own. The juvenile died when it was around 39 - 77 days old, likely due to thirst and starvation brought upon by the harsh droughts and conditions of the Maevarano Formation.

Despite their large size, *Rapetosauruses* are shown to be quite curious of other animals, even those smaller than them. This interest can be irritating for some creatures like *Beelzebufo*, with one male losing his temper and forcing the giant sauropod away by leaping and hissing at it. This reflects how, even today, large animals may unintentionally disrupt the mating and breeding activities of frogs and toads.

### Keystone Species Status

***“ Luckily for him, there's one thing that Rapetosaurs enjoy even more than wallowing in mud, and that is food. The hungry herd moves on, although not without leaving something useful behind. Dozens of giant footprints, full of water. Perfect for a Beelzebufo to continue his quest for a mate. ”***

― **David Attenborough**, *Swamps*
Much like elephants and other large animals today, *Rapetosauruses* are depicted relieving themselves with mud baths to clear away parasites and keep themselves cool. In the process, however, as they wallow and leave behind their footprints in the mud, they end up reshaping their landscape, modifying and even creating new habitats for smaller creatures like *Beelzebufo*. *Rapetosaurus* essentially appears to be a keystone species, a type of creature that plays a great effect on its natural environment, befitting given how *Rapetosaurus* is named after "Rapeto", the creator of the island of Madagascar according to Malagasy folklore.

## References

### General

1. ↑ Estimates of body size and geological time of origin for 612 dinosaur genera (Saurischia, Ornithischia)
2. ↑ 2.0 2.1 As stated in Swamps
3. ↑ 3.0 3.1 3.2 Dinosaur Facts and Figures. The Sauropods and Other Sauropodomorphs
4. ↑ 4.0 4.1 *Rapetosaurus krausei*: Tiny titanosaurus was just a few weeks old, scientists say
5. ↑ 5.0 5.1 Lap Dinos? Gigantic Sauropods Started Out Chihuahua-Size

### Dr. Darren Naish

1. ↑ Most (but not all) titanosaurs lacked fingers, though some of the titanosaurs on Prehistoric Planet were incorrectly modeled with thumb claws. Several tools and techniques were used to simulate sauropod tracks and wallowing traces in the Lower Zambezi National Park in Zambia, including a plastic bin that served as a makeshift sauropod foot.
2. ↑ Anurans seek out pools to serve as a mating and breeding base, calling out females by vocalizing, and they may even plan ahead by forming special spawning pools, channels for tadpoles to travel from area to area, and even providing food for their young every day. Their activities could be interrupted and ruined (albeit unintentionally) by larger animals, like *Rapetosaurus* in the case of *Beelzebufo*.