Understanding the Relationship Between Hyenas and Dogs
Though hyenas may resemble dogs in appearance and behavior, they are not closely related. This common misconception stems from their similar physical features and social behaviors. However, in terms of evolutionary classification, hyenas are much closer to cats than to dogs.
Taxonomic Classification
Both hyenas and dogs belong to the order Carnivora, which comprises meat-eating mammals. From here, the order divides into two suborders:
- Caniformia – the "dog-like" carnivorans, including dogs, bears, weasels, raccoons, and pinnipeds.
- Feliformia – the "cat-like" carnivorans, including cats, mongooses, and hyenas.
Hyenas are firmly placed within Feliformia, making them more closely related to felines than to canines.
Evolutionary Divergence
Hyenas and dogs diverged tens of millions of years ago. Dogs (family Canidae) arose within the Caniformia suborder, which diversified primarily in North America and Eurasia. In contrast, hyenas evolved within the Feliformia suborder, which primarily diversified in Africa and Asia. This divergence led to distinct evolutionary paths and adaptations.
Similarities and Convergent Evolution
Despite their different evolutionary origins, hyenas and dogs exhibit some similar traits due to convergent evolution. This occurs when unrelated species evolve similar features due to similar environmental pressures:
- Non-retractable claws
- Powerful jaws and teeth for carnivorous diets
- Social, pack-like behaviors
These traits can mislead observers into believing that hyenas are members of the dog family. But these are simply adaptations to similar ecological roles.
Caniformia Overview
The Caniformia suborder, to which dogs belong, includes nine extant families:
- Canidae – dogs, wolves, foxes
- Ursidae – bears
- Ailuridae – red panda
- Mephitidae – skunks, stink badgers
- Mustelidae – weasels, otters, badgers
- Procyonidae – raccoons, coatis
- Phocidae – true seals
- Otariidae – eared seals, sea lions
- Odobenidae – walruses
Dogs evolved within the Canidae family, which includes around 35 species and is separated into two main tribes: Canini (true dogs) and Vulpini (true foxes).
Feliformia and Hyenas
In contrast, hyenas belong to the Hyaenidae family within the Feliformia suborder. Although they are unique in their build and behavior, their closest relatives include mongooses and civets, not dogs. Hyenas share several anatomical and genetic features with feliforms, particularly in their skull structure and reproductive anatomy.
Genetic and Anatomical Differences
Caniforms and feliforms differ significantly in several anatomical ways:
- Auditory bullae: Caniforms have single-chambered bullae; feliforms (including hyenas) have double-chambered structures.
- Claws: Most caniforms have nonretractile claws, while feliforms, even hyenas, may use claw retraction differently.
- Baculum (penis bone): It's typically longer in Caniformia and absent in most Feliformia.
- Feeding behavior: Caniforms tend to be omnivorous; feliforms are generally more specialized carnivores.
Conclusion
While hyenas and dogs may seem similar at first glance, they represent two distinct evolutionary paths within the order Carnivora. Dogs are caniforms closely related to wolves, foxes, and even seals, while hyenas are part of feliforms and thus more akin to cats and mongooses. Understanding this difference underscores the fascinating complexity of mammalian evolution and helps dispel a common myth about hyenas’ identity.
