Grukk

**Grukk** (*ɢɾʊg*) are a spacefaring humanoid species originating from the planet Baag. Enormous for humanoids, Grukk are remarkably broad-shouldered, tall and physically strong and are thus often employed in labor-intensive or dangerous work. Grukk are closely related to amphibians and require massive water intake to maintain their cutaneous respiration. Ordinarily Grukk heal slowly, however they are able of consciously entering a state of *metarhythmesis* wherein their physical capabilities are drastically reduced but they are capable of regenerating almost any injury.

Around 80% of Grukk are citizens of the Universal Federation, with a further 15% belonging to the [[tba]].

## Biology

### Anatomy and Physiology

Like many spacefaring species, Grukk possess a humanoid body plan, consisting of two legs, a torso, two arms, a neck and a head. Male and female Grukk are similar in height, with the average height of males estimated to be about 6'4" with females being about 6'3". The most noteworthy sexual dimorphism between male and female Grukk is the presence of developed mammary glands in females and greater fat distribution towards the arms in males. The arms of male Grukk are incredibly large, averaging roughly 22 inches in diameter, while females' arms are only about half this. The entire body of a Grukk - particularly their arms and torso - possess extreme densities of muscle fibers, making them immensely physically strong.

Grukk have a largely homogenous pale green to bluish skin owing to the watery conditions on Baag. Their skin is remarkably smooth and rubbery, giving them some resistance to blunt impact and even sharp objects, however their scar tissue develops tough and withered. Some Grukk have a ring of small horns along their cheekbones and jaw, however the development of these protrusions varies between individuals. Grukk possess two pairs of large canine teeth.

#### Metarhythmesis

Grukk are a metarhythmic species: with conscious effort, a Grukk can enter a semi-dormant stage where they become incredibly weak as their body recycles all manner of internal materials in order to regenerate lost or damaged tissue. Depending on the extent of damage, a Grukk's metarhythmesis can take weeks, months or even years, during which time their musculature will shrink substantially and they will experience constant fatigue whilst still needing to maintain the same level of caloric intake. In this way, a Grukk can renew scar tissue and even regrow lost limbs and organs, however they will substantially shorten their lifespan in the process, such that some Grukk (especially the already elderly) may choose not to undergo metarhythmesis despite limb amputation, perhaps opting for prosthetic alternatives.

It is speculated that the advent of metarhythmesis, on Baag unique to the Grukk and their closely related ancestors, may have been crucial in the their development of advanced society and their emergence as their planets' archspecies, as it required the simultaneous evolution of compassion and exceptions to inbuilt social structures in order to be viable.

### Diet

Grukk are largely carnivorous, accustomed to the range of fish and megafauna of their homeworld.

### Reproduction, Life Cycle and Gender

Grukk are sexually dimorphic and exhibit many standard humanoid sex characteristics (males possess testes and a penis, whilst females posses an ovum and vagina). Anthropological evidence suggests that Grukk historically organized in harem groups, with one dominant male, a subservient male and a group of females (and their offspring), usually five or six. Female Grukk possess sperm storage tubules and can retain semen within their womb for up to three weeks after insemination, though male Grukk ejaculate with enough force to mostly displace any semen being retained, most likely so that a new alpha may ensure the germination of his own offspring.

Grukk are a protogynous species, with females able to change sex to male. The process usually takes only a few short months and was historically triggered by the absence of an alpha male or the presence of one perceived to be infirm. Notably protogynous females do not lose their breast tissue unless they undergo metarhythmesis and can even lactate for up to four years after transformation. However, since the advent of modern Grukk civilization, spontaneous protogyny has become much rarer, and almost exclusively occurs as a matter of conscious choice.

Grukk pregnancy usually takes around five months, whereafter the young are typically carried for a period of up to four months until they can walk on their own. The lifespan of a Grukk is relatively short for a humanoid, with most not exceeding the age of sixty-five. Sexual maturity is usually achieved by Grukk at age eleven, however Most Grukk cultures consider the age of adulthood to be around fifteen.