There has already been, since the late 1970s, much work done to show that whales and dolphins, collectively called cetaceans, evolved from exclusively land-dwelling mammals. Now it appears there is a case to be made that most of the fish we see in oceans today actually arose from freshwater ancestors.
96% of all fish on Earth are in the group called ray-fins. Research summarised by New Scientist shows that 75% of ray-fins share a heritage that arose in freshwater environments. They moved into pelagic habitats perhaps 170 million years ago.
So what happened to the organisms that never left the oceans? Mass extinctions, probably – for instance 95% of marine organisms were extinguished in the Permian-Triassic’s Great Dying – with freshwater habitats somewhat protected from disaster.
This is an older article, but I woke up to a gift of half a mouse my cat left for me on the carpet last night, so I figured a feline-related story was called for.
Seems that testosterone levels in cats impart a preference for the use of left or right paws.
A test for cats consisting of tasks of varying difficulty – from playing with a toy to manipulating a piece of food out of a tight spot – found that, under pressure to complete a tricky task, toms tended to use their left hands and females, their right.
More detailed overview here.
Picture via the inestimably marvellous icanhascheezburger.com
Now we can add giant eagles the size of hang-gliders to the list of New Zealand’s characteristic fauna.
The New Zealand Herald ran a story this week about a giant raptor, Haast’s Eagle, which seems to be the basis for Maori legends of man-eating birds. Recently revisiting the few fossils available of the birds, and using newly available technology, paleontologists have been able to better predict the lifestyle of these massive predators that became extinct only 500 years ago.
Because New Zealand was always so isolated geographically from the rest of the world, birds took over the ecological niches that mammals evolved to exploit elsewhere. This explains the unique birdlife of the islands including the kiwi, moa and Haast’s eagle.
And I love the line from the newspaper quoting Canterbury Museum curator Dr. Paul Schofield: “Haast’s eagle wasn’t just the equivalent of a giant predatory bird. It was the equivalent of a lion.”
Yep. A flying lion, possessed of a 3m wingspan and 4cm long talons, that could reach speeds of 80km when diving onto its unsuspecting prey! Yowsah.
Image acknowledgement: John Megahan
See, there’s this … thing… I really want to buy. And it’s kind of really old. And there aren’t too many of them around. Certainly haven’t been in the last 60-70 million years… And there’s an auction coming up – October 3, actually, in Las Vegas – where I can buy one. But only if I have about $10 million.
More here. (via Wired.)
There are squids bigger than Giant Squids, as it turns out. The Colossal Squid (!), a sample of which was caught by New Zealand fishermen last year, is just such a beastie.
The squid in the photo above weighs 485kg and is more than 4 metres long.
There is a tendency amongst species that dwell below the lowest levels of light penetration in the deep ocean to be much larger than related species living in shallower water. The colossal squid is a fantastic example. Of course, there are lots of implications for the appearance and behaviour of these organisms – their feeding habits etc are quite unique – and the squid seen above is, compared to the beaks of other squids found in the stomachs of sperm whales, appears to be a small example of its kind.
Photo courtesy of ABC Science.
Nick-named by the Oslo Uni team of paleontologists who discovered it, the Monster – a Jurassic era pliosaur – looks to be the largest marine reptile ever.
Measurements of parts of the partial skeleton discovered in the Svalbard archipelago (within 1000km of the North Pole) indicate that the creature was probably around 15 metres in length. The previous record holder was an Australian discovery: the kronosaur, outlined above along with a very unlucky diver, at a comparatively measly 10 metres.
Pliosaurs were at the top of their food chain more than 150 million years ago. Gigantic crocodile-like carnivores, their streamlined body shape, powerful flippers and mouthful of sharp, conical teeth would have struck terror into their prey.
Together with The Monster, the Norwegian team also discovered the fossilised remains of a long-necked plesiosaur and an icthyosaur. These discoveries will keep Oslo Uni paleontologists busy for several years to come!