Lagomorpha

Rabbits, hares, and pikas are in a group.

They are shaped like hares. They have four teeth in their top jaw. These teeth never stop growing. They must chew plants to keep them short.

Rabbits and hares have strong back legs. This helps them jump and run fast. Pikas are small and live in mountains. They make piles of dried plants for winter.

These animals are very special to see.

Lagomorphs are a group of animals. This name means "hare shaped."

They include rabbits, hares, and pikas. There are 110 known species today.

One big way to know a lagomorph is by its teeth. They have four teeth in their top jaw. These teeth grow all the time. They must chew tough plants to keep them short.

Most lagomorphs only eat plants. They do not eat meat like some rodents do.

Rabbits and hares belong to the family Leporidae. They have strong back legs to jump.

Hares are often medium in size. They live alone. Most rabbits are small. They often live in groups.

Some rabbits live in burrows under the ground.

Pikas are in the family Ochotonidae. They are small mammals. They live in rocky mountains. Pikas do not sleep through the winter. They make haypiles of dried plants. They eat these piles when it is cold. Pikas have almost no tail. Their legs are nearly the same length.

Lagomorphs are a special group of small mammals. The name comes from Greek words that mean "hare shaped."

This group includes two main families. The first is Leporidae, which contains rabbits and hares. The second is Ochotonidae, which includes pikas. There are 110 different species of lagomorphs alive today.

They live on every continent except for Antarctica. They are not found in Madagascar or the West Indies. Some lagomorphs, like rabbits, are even kept as pets in homes.

Lagomorphs have a very interesting way of eating. They are almost strictly herbivorous, which means they eat plants.

Their teeth grow continuously throughout their lives. Because of this, they must chew on tough, fibrous food to keep them from getting too long. They have a special way to get nutrients from hard plants. They use a process called cecotrophy. They ferment fiber in a part of their gut called the cecum. Then, they produce soft pellets called cecotropes and eat them again to absorb the nutrients.

Scientists have studied these animals for a long time. In 1811, Johann Karl Wilhelm Illiger first noted they were different from rodents. He called them Duplicidentata because of their teeth.

Later, in 1855, Johann Friedrich von Brandt created the name Lagomorpha. In 1912, James W. Gidley officially described them as a full order. Fossil evidence shows they were much more diverse in the past. The fossil record shows over 230 species and 75 different genera once lived.

There are many ways to tell lagomorphs apart from rodents. One big difference is their teeth. Rodents only have two incisors in their upper jaw. Lagomorphs have four incisors, including two smaller peg teeth behind the large ones.

Their bodies are also unique. For example, lagomorphs do not have paw pads. Instead, the bottoms of their paws are covered in fur. This is a trait they share with red pandas. In many species, the females are actually larger than the males.

Each family within the group has its own way of living. Hares are often solitary and use long legs to run fast.

Rabbits are often smaller and can live in large colonies in burrows. Pikas are small mammals that live in rocky mountains. Since they do not hibernate, pikas make "haypiles" of dried plants. They store these piles to eat during the cold winter months. These different habits help each animal survive in its own home.

Lagomorphs are a distinct order of mammals characterized by their unique dental and physical traits. The name Lagomorpha is derived from Ancient Greek terms meaning "hare shaped."

This group includes two living families: Leporidae, which contains rabbits and hares, and Ochotonidae, which contains pikas. Currently, there are 110 species of lagomorphs alive today. These animals inhabit almost every continent on Earth, with the exception of Antarctica, Madagascar, and the West Indies. While they are not native to Australia, humans have introduced them there, where they have successfully colonized many areas.

One of the most important ways to identify a lagomorph is by examining its teeth. While lagomorphs are closely related to rodents within the grandorder Glires, they possess significant differences. Most notably, lagomorphs have four upper incisors, which includes two smaller peg teeth located behind the larger ones. In contrast, rodents only have two upper incisors.

Like rodents, a lagomorph's incisors grow continuously throughout its life. This growth requires the animal to constantly chew on fibrous plant material to prevent the teeth from becoming too long. Additionally, while only the incisors of most rodents grow continuously, all of a lagomorph's teeth exhibit this continuous growth.

Lagomorphs have developed specialized biological processes to survive on a strictly herbivorous diet. Because they eat tough, fibrous plants, they must extract nutrients efficiently through a process called cecotrophy. First, the animal ferments fiber within a specialized part of the gastrointestinal tract called the cecum. This process produces soft pellets known as cecotropes. The lagomorph then reingests these cecotropes to absorb the nutrients in the small intestine. This method allows them to utilize energy from hard-to-digest vegetation that might otherwise be wasted. Like rodents, bats, and some insectivores, lagomorphs also possess a smooth-surfaced cerebrum.

There are two primary families within the order, each with different physical adaptations. The family Leporidae includes both rabbits and hares. Hares, belonging to the genus Lepus, are medium-sized mammals with long, powerful hind legs and large ears. They are often solitary and rely on speed and a "jinking" gait to escape predators.

Rabbits are generally smaller than hares and often live in colonial groups within burrows or nests called forms. The second family, Ochotonidae, consists of pikas. Pikas are small mammals, often with greyish-brown fur and almost no tail. Unlike leporids, pikas lack a highly arched skull and strong, long hind limbs. They are often found in mountainous regions, where they collect dried vegetation to create "haypiles" for winter food.

History shows that the lagomorph lineage has changed significantly over millions of years. In 1811, Johann Karl Wilhelm Illiger first distinguished them from rodents by calling them Duplicidentata. In 1855, the German naturalist Johann Friedrich von Brandt coined the name Lagomorpha. The group was not formally described as an order until American paleontologist James W. Gidley did so in 1912. Fossil evidence suggests that lagomorphs were much more diverse in the past. The fossil record contains approximately 75 genera and over 230 species, indicating that modern lineages may be in decline.

Evolutionary studies continue to refine our understanding of where these animals came from. In the late 20th century, many scientists believed the ancestor of lagomorphs was Eurymylus, a mammal from eastern Asia. However, 21st-century examination of fossils suggests they may instead descend from mimotonids. These were mammals in Asia during the Paleogene that shared similar body sizes and dental structures with early European rabbits like Megalagus turgidus. Some studies from 2008 even suggest an Indian origin, proposing that lagomorphs evolved in isolation when India was an island continent during the Paleocene.

Lagomorphs also exhibit unique reproductive and physical characteristics compared to other mammals. For instance, they are unusual among terrestrial mammals because the females are typically larger than the males. Their paws also differ from most mammals; instead of having paw pads, the bottoms of their feet are entirely covered in fur. This is a trait they share with red pandas. In terms of reproduction, many species produce large litters several times a year. While hares are precocial, meaning their young are born with eyes open and full fur, rabbits and pikas are altricial. This means their young, called kits, are born with their eyes and ears closed and without fur.