The animal kingdom is replete with diversity in body shape, size, and function. Unrelated animals share body features, such as fins, horns, or tusks. Whether you look at the smallest insects or the largest mammals, each one has traits that allow it to identify food, communicate with others of its own species, and maintain its safety.
In this article, we’ll look at six groups of animals and which kinds have horns. These taxonomic classes separate animals into groups based on distinct traits and features.
Let’s get started.
Why do Animals Have Horns?
Horns are a type of adaptation on the bodies of some animals. They are located on the head of the animal. True horns are only found in mammals, one of the groups of animals we’ll address today.
These true horns are made of living bone tissue, keratin, and other materials. Other groups of animals like birds and reptiles may have ‘horns,’ but these are usually not true horns. They are simply growths on the top of the head that look like horns.
The purpose of horns varies depending on the species of animal. Many mammals with horns are herd-dwelling herbivores. Such animals usually have a mating system where solitary males defend a harem or fight for the right to mate with females. They use their horns to ram and injure their competitors.
Non-mammalian animals with so-called horns usually don’t use them to fight. They may be more decorative than utilitarian. Some exceptions can be made with reptiles, but cases are few far and between.
Other animals’ horns are not horns at all, but types of sensory organs that help them understand their surroundings. The label ‘horn’ is occasionally misleading because growths on an animal’s head can be mistakenly labeled as such, even if they are not.
11 Types of Animals with Horns
This list is by no means comprehensive of all animals with horns. We highlight some of the most popular and common animals with horns and hornlike growths. We’ll tell you about their habitat, scientific names, and some of their behavioral traits.
The mammal group has the most animals with true horns. As we discussed, true horns require a core of living bone. Keratin or other hard protein-based structures surround the bone. Sometimes, the bone is hollow.
It’s important to remember that antlers are different than horns. Horns are permanent, while antlers grow on a yearly basis and fall off through natural causes.
1. Texas Longhorn
Scientific name: Bos taurus
The Texas longhorn is a unique breed of cattle that has extremely large horns. These horns are true horns – that is, they are made of bone – and are used for defense against predators and other threats.
Bulls and cows have horns. Calves are born with small nubs that eventually grow into full horns.
Scientific name: Aepyceros melampus
The Impala, which are native to Africa, are antelopes that live in the savanna region of the continent. They graze in large herds that move seasonally across the landscape.
Their horns are true horns, and they protrude up and back from the head in a slightly bent shape. Only males have horns. They use them to fight each other for access to choice females.
Birds do not have true horns like mammals do. Their ‘horns’ are modified feathers that stick up from the sleek head feathers or modified skin cells. The number of horns varies depending on the species of bird.
Some birds’ horns disguise their eyes or create optical illusions that give them the appearance of looking bigger than they really are.
3. Great Horned Owl
Scientific name: Bubo virginianus
The great horned owl is the second heaviest species of owl in North America. Only the snowy owl is larger. Great horned owls reign supreme over territories.
They are extremely aggressive when they encounter other owls. Their diet consists of anything they can pick up.
This bird’s horns are not protrusions of bone or skin. They are tufts of feathers that scientists call plumicorns. Plumicorns are identifying markings that help great horned owls tell each other apart.
The hoot of a great horned owl is one of the easiest ways to identify it. The vocalization actually sounds like a “hoot” compared to the burble or screech of other owl species.
4. Horned Screamer
Scientific name: Anhima cornuta
The Horned screamers are native to central South America and the Amazon River basin. These waterbirds spend most of their lives in wetlands and marshes; they have chicken-like beaks but otherwise behave like ducks or geese.
Unlike other horned birds, the horned screamer’s horn is not made of modified feathers. Instead, cornified cells grow up to 6” long from the skin. Cornification is a word to describe the process of skin becoming scaly and hard.
The horn on the horned screamer gives it a unicorn-like appearance. These birds make prolific vocalizations that sound like screams and whoops.
Reptiles include snakes, lizards, and turtles. Some horned reptiles have ‘true horns,’ meaning their horns have a living bony core. Others simply boast modified scales that look like horns.
Depending on the species, these animals use their horns to fight one another or scare off predators.
5. Texas Horned Lizard
Scientific name: Phyrnosoma cornutum
The Texas horned lizards are small desert-dwelling reptiles that live in Texas, the Southwest, and the southeastern United States. They get their name from the small crescent-shaped horns at the crown of the skull.
While they are fearsome up close, they don’t pose a threat to people – a Texas horned lizard measures a maximum of 5” long. This lizard uses its horns to deter predators from attacking; nobody likes a sharp, spiky meal.
6. Jackson’s Chameleon
Scientific name: Trioceros jacksonii
The Jackson’s chameleon is a colorful, slow-moving lizard native to Eastern Africa. They are common in the pet trade because of their ability to change colors to match their surroundings. You might be surprised to learn that males have a greater camouflage capability than females.
Only males are horned. They have a horn over each eye and one between their nostrils. Males use them to fight each other over access to female chameleons.
Amphibians are similar to reptiles with a few exceptions. While reptiles can spend most of their lives away from water, amphibians cannot. They rely on external water sources to incubate their eggs.
They also have vascularized skin, meaning they can respirate, or breathe, through their skin. This superpower makes them vulnerable to drying out.
7. Casque-headed Treefrog
Scientific name: Hemiphractus spp.
Casque-headed treefrogs are native to the Western Hemisphere, where they live in the rainforests of Central and South America. This name describes six species of frogs.
Their body coloration helps them blend into low underbrush, where they pass as dead leaves. The ‘horns’ on these frogs’ bodies are just behind the eyes, camouflaging what would otherwise be a round froggy head into a diamond-like leaf shape.
What’s interesting about casque-headed tree frogs is that they incubate their babies on a special patch on their backs. In the humid jungle, there is enough airborne moisture to keep the eggs hydrated as they grow directly into adults – they skip the tadpole stage.
8. Argentine Horned Frog
Scientific name: Ceratophrys ornata
The Argentine horned frog can be found only in Argentina. It has an especially wide mouth and can spread its body out very flat. They measure between 4.5” and 6.5”.
Adults are a kaleidoscope of colors: yellow, black, green, and red all swirl about in a pattern of spots and rings.
This frog’s horns are not true horns. They are pointed protrusions above the eye. These protect the frog’s eyes, as frogs lack eyelids, and camouflage the amphibian against substrate and leaves.
It is scientifically impossible for an invertebrate to have horns. This is because invertebrates lack a backbone, and thus, bones. True horns require living bone tissue.
However, some invertebrates have appendages that mimic the appearance of horns. Soft-bodied aquatic invertebrates may use these horns to augment their sense of touch. Chitinous invertebrates like insects may have bony horns that help them avoid being eaten by predators.
9. Rhinoceros Beetle
Scientific name: Dynastinae gn. spp.
The rhinoceros beetle gets its name from the rhino-like horn that protrudes from the center of its face. There are about 1,500 different species of rhinoceros beetle; they live on every continent except Antarctica.
Only males have a large horn. Differences between males’ and females’ appearance are called sexual dimorphism. This is one indicator that fighting between males is part of a species’ mating ritual.
Rhinoceros beetles are no different. Males engage in intense fighting over the courtship of females.
Fish with ‘horns’ are rare, but they exist. It’s important to know that horns on a fish are not like horns on mammals or reptiles. Fish are soft-bodied creatures with scales.
Their bones are light and not equipped to bear the weight of horns. When a fish does have ‘horns,’ that usually means it has scales or some kind of fin on its head that resembles horns on a terrestrial animal.
10. Longhorn Cowfish
Scientific name: Lactoria cornuta
The longhorn cowfish is named after the longhorn cow, a breed of cattle with massive horns. Like the cow, the longhorn cowfish has two horns that emerge from its forehead just above its eyes. They are easy to recognize thanks to both the horns and their bright yellow scales.
Longhorn cowfish use their horns to defend themselves against predators. Unlike other horned animals, their horns, which are made of collagen fibers, can grow back if broken off in fights. Both males and females have horns.
11. Whitemargin Unicornfish
Scientific name: Naso annulatus
Underwater, one horn is much more common than two horns. This is because most fish are laterally compressed. When viewed head-on, a fish’s body is taller than it is wide.
This is an evolutionary result of water’s effects on fish; it’s easier to move through the water with a thin body. There is less drag.
The whitemargin unicornfish is a prime example of this phenomenon. Its laterally compressed body supports one horn in the center of its forehead. The fish, which measures about 40”, usually has a horn about 7” long.
- “The Integumentary Morphology of Modern Birds – An Overview,” Peter R. Stettenheim, American Zoologist, August 2000, doi.org