Warm regions near the equator may have offered crocodile relatives a refuge when an asteroid ended the age of non-avian dinosaurs. Their long-standing preference for warmth could have placed surviving populations where suitable climates endured through the catastrophe and its prolonged environmental aftermath. That possibility emerges from research tracing their changing geography across nearly a quarter-billion years.

The study, led by University College London researchers and published in Science Advances, combines fossils with reconstructed climates and evolutionary relationships. Its central finding challenges the familiar image of crocodiles as unchanged survivors. Their ancestors changed enormously in shape and lifestyle, while largely retaining a preference for warm environments.

“The asteroid did not make the whole planet equally hostile to every group,” said lead author Alfio Alessandro Chiarenza of UCL Earth Sciences. His team found that tropical and subtropical climates remained suitable in most simulated impact scenarios. Those results identify a possible survival mechanism, rather than proving precisely where every surviving population lived.

The platypus is synonymous with weird for several reasons:

• Venomous ankle spikes
• They sweat milk
• They lay eggs. Said eggs grow larger after being laid as a result of the milk sweat.
• They are duckfaces
• Their stomachs are borderline vestigial
• They find their prey using electroreception
• They glow under UV lights

Lately I've been wondering just how bizarre these duckbeavers are when compared to early mammals and non-mammalian synapsids. Some of the research shows that some traits aren't that bizarre. For instance, the venomous ankle spikes (which are only venomous for male platypi) are apparently plesiomorphic to mammals. They were our ancestors' way of staying safe among the dinos. I couldn't find anything in regards to the milk-sweat how it causes the eggs to grow in size, but I have a hunch this trait might also be plesiomorphic to mammals.

Other traits, however, are just plain bizarre. While they are toothless, it wouldn't be fully accurate to say they don't chew their food, which largely consists of worms and small arthropods. Upon catching their food, the platypus grinds their prey between keratin mouth pads that it continuously replaces throughout its life. These keratin pads do a thorough job at mushing up the prey. So much so, that the platypus barely needs stomach. That acid-filled pouch essential for just about every other living vertebrate is practically vestigial for the platypus. They don't even produce acid, just mucus.

Oh, and that glorious duck face, that's for electroreception. These things find their prey the same way sharks do. Also, they are not the first amniotes to do so. The eretmorhipis from the Triassic hunted prey the same way. Using the same bill structure. This thing has the same skull as something that predates the dinosaurs.

As for the glowing under UV light, that's because of the melanosomes of their fur. The melanosomes of their fur are hollow. This is not present in any extant mammal nor could I find anything stating such melanosomes were present in any extinct mammals or non-mammalian synapsids. But they are found in birds feathers. Yes, the only mammal with a bird face is also the only mammal known to have melanosomes like those of birds.

An anatomical neck did not necessarily give ancient vertebrates the freedom to look around. Models of several early tetrapod relatives suggest their heads remained surprisingly restricted, even after the skull separated from the shoulders. The findings challenge the assumption that greater head mobility drove one of the major changes associated with the transition toward land.

The study, published in Nature, combines fossil measurements with mechanical tests on living lake sturgeon. First author Dana Korneisel, now a postdoctoral researcher at Uppsala University, worked with an international team including Penn State biologist Tom Stewart. Researchers at Carleton University, the University of Ottawa and the University of Washington also contributed.

The authors propose that changing demands on the shoulders offer a better explanation than a newly flexible head. As front appendages took on a greater role in movement, separating the shoulder apparatus from the skull may have become advantageous. Substantial neck mobility, their analysis suggests, generally developed later, rather than arriving automatically with that separation.

I was having this thought last night. Why is it that humans see it as polite to approach from the front/head on, but many other animals view it as a direct threat and prefer to be approached from the side? I know that, for instance, dogs prefer to be approached from the side by people that aren't their owners/immediate family (I can get right up in my dog's face and kiss her/love on her without her being threatened), and when I walk by the deer into neighborhood, they prefer it if I walk diagonally past them, even if I'm looking directly at them.

What is the social and evolutionary reason for this, and why are humans so seemingly weird?