Proboscidea

Elephants and their old friends are special.

They have long noses. They also have big tusks. Some of these animals lived a long time ago.

They were very, very large!

Some old friends were even bigger than today's elephants. They grew large to eat plants. Their legs grew long to help them move.

Their feet became wide to hold their weight.

These animals lived in many lands. Some lived in Africa. Others lived in North America. Some even lived on small islands.

On islands, some elephants grew very small. This happened because they had less food. They were much smaller than big elephants.

It is fun to learn about these giants.

Proboscideans are a group of large mammals. This group includes modern elephants and many extinct relatives.

Today, only three species of elephant live on Earth. These are the African bush elephant, the African forest elephant, and the Asian elephant.

Long ago, proboscideans were much smaller. The earliest member, Eritherium, lived about 60 million years ago. It was very tiny compared to modern elephants. Over time, these animals grew much larger. Some old species, like the mastodon Mammut borsoni, were giants. They may have been the largest land mammals ever.

As they grew, their bodies changed too. They developed long, muscular trunks. They also grew large tusks made of dentine.

Their teeth changed to help them eat grass more easily.

Some proboscideans lived on islands. On these islands, they experienced dwarfism. This means they grew much smaller than their cousins on the mainland. They grew small because food was limited.

Some small mammoths lived on islands as recently as 4,000 years ago.

Proboscidea is a special group of large mammals. This group includes the elephants we see today and many extinct relatives.

There are three living species of elephant left on Earth. These are the African bush elephant, the African forest elephant, and the Asian elephant. The group also includes many animals that are no longer alive. These extinct relatives include mastodons, mammoths, and gomphotheres. Some of these animals were the largest land mammals to ever live.

These animals changed a lot over millions of years. Early proboscideans were much smaller than the elephants we know. For example, Eritherium lived about 60 million years ago in Africa. It had a body mass of only about 20 kilograms. Later, animals like Barytherium grew much larger, reaching about 2 tonnes. As they grew, their bodies developed new features. They grew long, muscular trunks to help them reach food. They also developed large tusks made of a material called dentine.

History shows how these animals moved around the world. About 18 to 19 million years ago, Africa and Eurasia collided. This allowed proboscideans to travel from Africa into Eurasia. Later, they moved into North America using the Bering Land Bridge. Around 10 million years ago, the first true elephant family members emerged in Africa. They grew out of a group called gomphotheres. Many different groups lived during the Miocene period. These included the deinotheres and the stegodontids.

Physical changes helped these animals survive in new ways. Their limbs grew longer to support their huge weight. Their feet became wider with thick cushion pads for support. The skull grew larger, and the neck became shorter to hold it up. Their teeth also changed to help them eat better. Most species developed larger cheek teeth to eat grass. This is called being hypsodont, which means having high crowns. Some species even had tusks that grew continuously.

Sometimes, these large animals lived in very strange ways. Some species lived on islands and became much smaller. This is called insular dwarfism. It happened because food was limited on the islands. One small elephant, Palaeoloxodon falconeri, was only about 1 meter tall.

Other proboscideans lived in herds, much like modern elephants do. Scientists think they might have used low sounds to talk to each other. This is called infrasound. Even the extinct mammoths lived in small groups on islands. Some survived on Wrangel Island until only 4,000 years ago.

Proboscidea is a taxonomic order of mammals that includes modern elephants and many of their extinct relatives.

This group belongs to a larger group of mammals called Afrotheria. It includes the three living species we recognize today: the African bush elephant, the African forest elephant, and the Asian elephant. Beyond living species, the order contains many extinct families like the deinotheres, mastodons, and gomphotheres. Some members of this order were among the largest land mammals to ever exist.

The elephant Palaeoloxodon namadicus and the mastodon Mammut borsoni were massive. These animals may have had body masses that rivaled or even exceeded the paraceratheres. The largest living member is the African bush elephant. It can reach a shoulder height of 4 meters and weigh 10.4 tonnes.

Evolutionary changes in Proboscidea involved a massive increase in body size. This growth likely helped them survive by allowing them to eat vegetation with low nutritional value. As they grew, their physical structures changed to support their weight. Their limbs became longer, while their feet became shorter and broader. They transitioned from a plantigrade stance to a digitigrade stance. This means they walked on their toes. To support this, they developed cushion pads and used the sesamoid bone for stability. The skull also grew larger, particularly the cranium. To help hold up this heavy skull, the neck became shorter.

One of the most famous features of later proboscideans is the trunk. The trunk is a long, muscular organ used for reaching food. This developed as the nasal regions of the skull retracted. Another major feature is the tusks. These are large teeth primarily made of dentine. In some groups, like the Elephantiformes, the second upper and lower incisors transformed into ever-growing tusks. In the Deinotheriidae family, tusks only appeared on the lower jaw.

The size of these tusks varied greatly. A mammoth tusk could weigh over 100 kilograms. Some primitive species, like Stegotetrabelodon, had lower tusks reaching 2.5 meters in length.

Teeth also underwent significant specialization. In the group known as Elephantimorpha, molar teeth were replaced horizontally rather than vertically. This is different from how most other mammals replace their teeth. Members of the family Elephantidae developed a specific type of tooth called hypsodont teeth. These are high-crowned teeth with parallel lophs, which are ridges on the tooth surface. This specialized shape made them much more efficient at grazing on grass. This change helped them adapt as their diets shifted from browsing on leaves to grazing on grass.

The history of Proboscidea began in Africa during the Paleocene epoch. The earliest known member, Eritherium, lived about 60 million years ago. It was very small, with a mass of only about 20 kilograms. By the late Eocene, Barytherium had grown to about 2 tonnes. Some early members, like Moeritherium, were likely semi-aquatic. A major turning point occurred during the Early Miocene, about 18 to 19 million years ago. The collision of Afro-Arabia with Eurasia allowed proboscideans to spread from Africa into Eurasia. Later, they moved into North America via the Bering Land Bridge.

Different groups dominated at different times. During the Miocene, groups like gomphotheres and amebelodontids were prominent. Around 10 million years ago, the first members of the family Elephantidae emerged in Africa from gomphotheres. During the Pleistocene, many non-elephantid groups went extinct. However, some species experienced insular dwarfism. This happened when populations became isolated on islands. Due to limited resources and fewer predators, they evolved to be much smaller. For example, the dwarf elephant Elephas falconeri was only about 1 meter tall.

Many proboscideans lived in social groups. Scientists believe the American mastodon lived in herds similar to modern elephants. These herds likely consisted of females and juveniles, while adult males lived alone. It is also thought that they communicated using infrasound. This is sound that is too low for humans to hear. While most non-elephantid groups died out during the Late Pleistocene, some mammoths survived on islands. A population of woolly mammoths lived on Wrangel Island until approximately 4,000 years ago.