New! Sign up for our free email newsletter.
Reference Terms
from Wikipedia, the free encyclopedia

Evolution of cetaceans

The cetaceans (whales, dolphins and porpoises) are descendants of land-living mammals, and remnants of their terrestrial origins can be found in the fact that they must breathe air from the surface; in the bones of their fins, which look like huge, jointed hands; and in the vertical movement of their spines, characteristic more of a running mammal than of the horizontal movement of fish. The question of how land animals evolved into ocean-going behemoths has been a mystery for a long time, owing to gaps in the fossil record. However, recent discoveries in Pakistan have managed to solve many of these mysteries, and it is now possible to see several stages in the transition of the cetaceans from land to sea. The most remarkable of the recent discoveries in Pakistan has been Ambulocetus, which looked like a three-metre long mammalian crocodile. Ambulocetus was clearly amphibious, as its back legs are better adapted for swimming than for walking on land, and it probably swam by undulating its back vertically, as otters, seals and whales do.

Related Stories
 


Plants & Animals News

October 8, 2025

Kobe University researchers found that orchids rely on wood-decaying fungi to germinate, feeding on the carbon from rotting logs. Their seedlings only grow near deadwood, forming precise fungal partnerships that mirror those seen in adult orchids ...
Researchers at KAUST have confirmed that the Red Sea once vanished entirely, turning into a barren salt desert before being suddenly flooded by waters from the Indian Ocean. The flood carved deep channels and restored marine life in less than ...
Scientists studying tiny roundworms have uncovered how the secrets of a long life can be passed from parents to their offspring — without changing DNA. The discovery shows that when certain cellular structures called lysosomes change in ways that ...
New research reveals that deep-sea mining could dramatically threaten 30 species of sharks, rays, and ghost sharks whose habitats overlap with proposed mining zones. Many of these species, already at risk of extinction, could face increased dangers ...
HydroSpread, a breakthrough fabrication method, lets scientists build ultrathin soft robots directly on water. These tiny, insect-inspired machines could transform robotics, healthcare, and environmental ...
Billions of years ago, Earth’s atmosphere was hostile, with barely any oxygen and toxic conditions for life. Researchers from the Earth-Life Science Institute studied Japan’s iron-rich hot springs, which mimic the ancient oceans, to uncover how ...
Fungi may have shaped Earth’s landscapes long before plants appeared. By combining rare gene transfers with fossil evidence, researchers have traced fungal origins back nearly a billion years earlier than expected. These ancient fungi may have ...
A team of researchers tested morin, a plant compound, against gum disease bacteria and found strong antimicrobial benefits. By encapsulating it in polymers, they created a powdered form for oral hygiene products. This could replace antibiotics, ...
Scientists have uncovered a dangerous hidden feature in Black Mamba venom that explains why antivenoms sometimes fail. The study revealed that several mamba species launch a dual neurological attack, first causing limp paralysis and then unleashing ...
Scientists have kept a tiny slice of cochlea alive outside the body, directly witnessing how hair cells amplify sound. The finding confirms a universal principle of hearing and could pave the way for long-sought treatments for hearing ...
Researchers have revealed how polymyxins, crucial last-resort antibiotics, break down bacterial armor by forcing cells to overproduce and shed it. Astonishingly, the drugs only kill bacteria when they’re active, leaving dormant cells untouched. ...
Human fertility hinges on a delicate molecular ballet that begins even before birth. UC Davis researchers have uncovered how special protein networks safeguard chromosomes as eggs and sperm form, ...

Latest Headlines

updated 12:56 pm ET