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Neoteny in Other Species
Neoteny has been observed in many other species. Neoteny in amphibians seems to be the most widely studied aside from humans; many examples of neoteny in other species stem from studies done mainly on salamanders. There is also a general prevalence of increased neoteny within domesticated animals like dogs. Neoteny has been noted in species similar to humans, like chimpanzees; the neotenous traits within the species that resemble those within humans may give some insight into the evolutionary history of humans. What can be gathered from many studies on neoteny in various species is that organisms with similar lineages tend to neotenize, retain similar features from the juvenile form into adulthood.

There is a distinct difference between partial and full neoteny in other species. Partial neoteny is the retention of the larval form beyond the usual age of maturation with the possibility of the development of sexual organs, progenesis, but eventually the organism matures into the adult form; this can be seen in Rana Clamata, a species of frog. Full neoteny is seen in Amblystoma tigrinum, the tiger salamander. This species is part of a larger group, perrenobranchiates. The species within this group are considered to be permanent larval forms which means that they are capable of reproducing and they do not evolve into adult forms. A few species of birds show partial neoteny. A couple examples of such species are Chiroxiphia linearis and Chiroxiphia caudata. The males of both species retain their juvenile plumage into adulthood, but eventually lose it once they are fully mature. It is important to note the difference between partial and full neoteny when looking at other species.

Neoteny is seen more in domesticated animals like dogs and mice. This is because there are more resources available, less competition for those resources, and with the lowered competition the animals expend less energy obtaining those resources. This allows them to mature and reproduce more quickly than their wild counterparts. Evolutionary neoteny can arise in a species when those conditions occur, and a species becomes sexually mature ahead of its “normal development”. Another explanation for the neoteny in domesticated animals can be the selection for certain behavioral characteristics. Behavior is linked to genetics which therefore means that when a behavioral trait is selected for, a physical trait may also be selected for due to mechanisms like linkage disequilibrium. Some common neotenous physical traits in domesticated animals (mainly dogs, pigs, ferrets, cats, and even foxes) include: floppy ears, changes in reproductive cycle, curly tails, piebald coloration, fewer or shortened vertebra, large eyes, rounded forhead, large ears, and shortened muzzle.

It is important to note that neoteny arises from a change in the timing of development; these changes occur at the genetic level, so it stands to reason that similar species will neotenize similar features independently of one another. Gene analysis involving sequences that determine neotenized features in the order Coleoptera, mainly beetles, showed that species with related lineages are likely to neotenize features, like retention of the larval form or features well into the age of sexual maturity, independently because they have similar gene sequences. Neoteny is a way to produce novel features through changes in timing and development as seen in these beetle species. Neoteny is commonly seen in flightless insects like the females in the order Strepsiptera. The flightless trait in insects has evolved many separate times; environments that may have contributed to the separate evolution of this trait are: high altitudes, isolation on islands, and insects that reside in colder climates.

Many species of salamander, and amphibians in general, are known to have neotenized characteristics. The axolotl is a species of salamander that retains its juvenile aquatic form throughout adulthood, which is an excellent example of full neoteny. Gills are a common juvenile characteristic in amphibians that are kept after maturation; a good example of this would be a comparison of the tiger salamander and the rough-skinned newt, both of which retain gills into adulthood.

Pygmy chimpanzees share many physical characteristics with humans. A prime example is their skulls. Pygmy chimpanzees show neoteny in the structure of their skulls. They retain the juvenile shape of the skull which does not change into adulthood, it only increases with size. This is due to sexual dimorphism and an evolutionary change in timing of development. Juveniles became sexually mature before their bodies had fully developed into adulthood, and due to some selective advantage the neotenic structure of the skull remained in later generations.

More examples of neoteny can be seen in these other species:
 * The families: Gerridae, Delphacidae, and Carabidae. Many of the insect species within these families have smaller, neotenous wings or no wings at all.
 * Some cricket species which shed their wings in adulthood.
 * Beetles of the genus Ozopemon; the males are thought to be the first known example of neoteny in the order Coleoptera. They are significantly smaller than the females and it is thought that the neoteny in males is linked to the inbreeding within species.
 * Kalotermes flavicollis: a termite that shows neoteny in females during molting.
 * The Northwestern Salamander: higher altitude causes greater neotenic tendencies.
 * The rook, Corvus frugilegus: the evolution of birds from dinosaurs may be linked to dimorphism through neoteny.
 * A few species of the family Ischnomesidae, crustaceans.