Fossil hunters have discovered the remains of the earliest ancestor of the modern whale: a small deer-like animal that waded in lagoons and munched on vegetation.
The latest fossils were discovered among rocks that were originally collected more than 30 years ago from an ancient site with hundreds of fossilized Indohyus bones found at Sindkhatudi, in the Kalakot region, in Kashmir, by an Indian geologist called A Ranga Rao. When he died a few years ago, Professor Thewissen began working on the remaining rocks after being given them by Ranga Rao's widow.
Whales are long suspected to have originated from four-footed mammals called artiodactyls that walked on land in South Asia and gradually adapted to live in the sea. The landmark finding represents a long-sought "missing link" in the 10m-year journey that saw ancient land mammals evolve into modern cetaceans, a group that includes whales, dolphins and porpoises. The latest discovery, named Indohyus, is the first whale ancestor known to have lived on land.
A team led by Hans Thewissen at the Northeastern Ohio Universities College of Medicine reconstructed a near-complete skeleton of the animal, close in size to a domestic cat, dating from 48 million years ago.
"The earliest whales didn't look like whales at all," Thewissen said. "It looked like a cross between a pig and a dog." They lost their legs and ability to walk on land about 40 million years ago, he said. And the Indohyus? "A tiny little deer maybe the size of a raccoon and no antlers," Thewissen said. He said it most resembles the current African mousedeer, which has a rat-like nose and "whendanger approaches, it jumps in the water and hides."
India and Pakistan were the general region where early whales lived. That matches with the Indohyus but not the early African hippos, Thewissen said. While modern-day cetaceans are known to be smart, early whales and Indohyus had small brains, the researcher said.
Analysis of the bones revealed they had a thick and heavy outer coating, a characteristic common among modern wading mammals such as hippos. Chemical tests on the animals' teeth found they were similar to those of aquatic animals, suggesting that Indohyus spent much of its time in water.
The first whales, Pakicetidae, emerged around 50m years ago and resembled land mammals rather than the giant marine creatures of today. These evolved into large, powerful coastal whales, or Ambulocetidae, that had big feet and strong tails. Later, whales lost their hind limbs and hair and developed powerful tail fins and flippers.
Indohyus was a herbivore, suggesting the earliest ancestors of whales took to the water and only later adapted their diet to become carnivorous.
Whale evolution is thought to have begun with creatures like Indohyus becoming more adapted to a watery environment to avoid land-based predators. The animal's heavy bones would have made Indohyus a slow beast on land, but in the water, they would help it stay on the bottom, where it could forage and hide.
Whales are long suspected to have originated from four-footed mammals called artiodactyls that walked on land in South Asia and gradually adapted to live in the sea. The landmark finding represents a long-sought "missing link" in the 10m-year journey that saw ancient land mammals evolve into modern cetaceans, a group that includes whales, dolphins and porpoises. The latest discovery, named Indohyus, is the first whale ancestor known to have lived on land.
A team led by Hans Thewissen at the Northeastern Ohio Universities College of Medicine reconstructed a near-complete skeleton of the animal, close in size to a domestic cat, dating from 48 million years ago.
"The earliest whales didn't look like whales at all," Thewissen said. "It looked like a cross between a pig and a dog." They lost their legs and ability to walk on land about 40 million years ago, he said. And the Indohyus? "A tiny little deer maybe the size of a raccoon and no antlers," Thewissen said. He said it most resembles the current African mousedeer, which has a rat-like nose and "whendanger approaches, it jumps in the water and hides."
India and Pakistan were the general region where early whales lived. That matches with the Indohyus but not the early African hippos, Thewissen said. While modern-day cetaceans are known to be smart, early whales and Indohyus had small brains, the researcher said.
Analysis of the bones revealed they had a thick and heavy outer coating, a characteristic common among modern wading mammals such as hippos. Chemical tests on the animals' teeth found they were similar to those of aquatic animals, suggesting that Indohyus spent much of its time in water.
The first whales, Pakicetidae, emerged around 50m years ago and resembled land mammals rather than the giant marine creatures of today. These evolved into large, powerful coastal whales, or Ambulocetidae, that had big feet and strong tails. Later, whales lost their hind limbs and hair and developed powerful tail fins and flippers.
Indohyus was a herbivore, suggesting the earliest ancestors of whales took to the water and only later adapted their diet to become carnivorous.
Whale evolution is thought to have begun with creatures like Indohyus becoming more adapted to a watery environment to avoid land-based predators. The animal's heavy bones would have made Indohyus a slow beast on land, but in the water, they would help it stay on the bottom, where it could forage and hide.
