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Today in biology

RPG.net has a thread on "what if the Cretaceous and early Iron Ages were mixed up somehow?" e.g. humans interacting with surprise dinosaurs and such. As often happens with silly geeky threads with well-selected geeks, I learned non-silly things.

The largest living reptile and land predator are the same animal, which I have never ever heard of before: the saltwater crocodile. With the largest range of any croc too, from east India through Indonesia to northern Australia, and individuals found as far as Japan, southern Australia, and east Africa. They're territorial/aggressive/stupid enough to attack boats in their territory, though I don't know exactly what that means behaviorally. Also, something distinguishing crocodilian+s from alligators is salt glands excreting excess salt, though no other croc is as marine as the saltwater.

Humpback whales are baleen whales, which means I always thought of them as big singing cows, grazing plankton or krill which might as well be plants. Wikipedia describes them as cooperative tool-using predators, hunting down schools of 'small' fish like Atlantic salmon by weaving bubble nets (which I've heard of, but I think from dolphins) and group tactics to herd the fish into nicely scoopable density. This had come up because of someone wondering about mosasaurs eating the same fish fishermen wanted, even if they didn't attack boats, and someone else saying fish already live with whale-sized predators.

Ah right, mosasaurs, last of the great marine apex predators, after icthyosaurs and then plesiosaurs. As big as sperm whales in the largest cases. Live birth seems common to all of them. It was suggested that if salties attack small boats, whale-sized mosasaurs might attack 15 foot fishing boats for the prey inside. I'm skeptical, but I've learned that one thing dumber than "Someone Is Wrong On the Internet" is "Someone has different untestable assumptions on the Internet."

Someone supporting the Doom Predators idea asked "have you seen a trireme? They're not that big." I have not but I did look them up. 37 meter lengths. 24 m for biremes. Phoenician merchant ships 16+m long and 6+m wide. Longships 16-36m in length. Vs. sperm whales and top mosasaurs of about 16 m in length. Would such animals attack a high-walled piece of wood as big as let alone bigger than they are? Would they continue to do so after being stabbed a few times by spears? Especially near the eye?

I also learned that T. rex was about as tall at the hip and as massive as male African elephants. T. rex is *long* but generally shown cantilevered, not standing up. The mass estimates are in dispute; some thing even those are too high, while others thing they could have massed up to 9 tons, as opposed to 5-7. Also it had lots of hollow bones... Forelimbs are infamously short but apparently really strong, suggesting non-vestigial function, perhaps to hold prey.

Currently research seems to say T. rex couldn't move faster than a human sprinter, if that (25 mph, 11 meter/s) and probably not properly run (have an airborne phase) at all, like elephants.

Triceratops is more massive, actually, 6-12m. And yes, it did co-exist with and have duels with T. rex. Not as long or as high, I guess thicker?

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