In 1952 Alan Turing, a british mathematician, logician, cryptanalyst, and computer scientist, wrote a paper which remains influential in computational biology today. He explained how stripes might form on a snake’s skin [and other patterns on animals], using the dispersion of two chemicals; an activator [red] and an inhibitor [yellow]. The activator causes the colouration, and the inhibitor inhibits it. Turing wrote a pair of equations which say that concentrations of the activator cause creation of more inhibitor, but that the inhibitor diffuses and spreads out more quickly than the activator. As shown in the animation, this causes the activator to form peaks with surrounding basins of inhibitor. The concentrations of the two chemicals quickly converge to a stripey pattern where the red activator is periodically in higher concentration than the yellow inhibitor. [video] [more] [code]
also ‘dove’ and ‘pigeon’
The Pinhole Eye of the Nautilus, by Marc Gosselin:
“The Nautilus is the only animal on the planet with pinhole eyes.”
I didn’t realize that mosasaurs showed up almost right after ichthyosaurs went extinct. Those conniving varanoids!
Help! How do I become an expert in penguins? Evolution/paleobiology, physiology, behavior, phylogeny, etc. I want to know everything there is to know about my favorite group of birds. But there doesn’t seem to be any books about ‘em…
The craniates are characterized by a skull; that is, a complex ensemble of skeletal elements which surrounds the brain and sensory capsules. The skull of hagfishes (top) consists of cartilaginous bars (blue), but the brain is mostly surrounded by a fibrous sheath (yellow), underlain by the notochord (green). The skull of lampreys (middle) has a more elaborate braincase and comprises a large “branchial basket” surrounding the gills. In the gnathostomes (bottom), the braincase is generally closed (after Janvier 1996b).
Got super discouraged by people calling animals the wrong name today, so I decided it was about time to post this little gem I’ve been sitting on for a while.
Ant-mimicking nymph of a longhorned grasshopper
This nymph of a (false) katydid or bush-cricket, ~2-3 cm, looks like a giant ant (mimicry);however, ants (Hymenoptera) neither have such - long - antennae nor such strong hind-legs (femur)! The colouration supports the mimicry: the dark colour of antennae is interrupted by a broad white part, hence they seem to be short like the ones of ants. The same happens with the colourful neon-stripes that legs seem thin and the body seems constricted… like a real ant!
Subfamily: Phaneropterinae, Family: Tettigoniidae
Table Mountain National Park, Gunung Meja, West Papua, Indonesia
(photo: Guido Bohne)
Northern or Single-Wattled Cassowary - Casuarius unappendiculatus
Cassowaries are one of the ratites - large, (generally) flightless birds. They inhabit the dense rainforests of Papua New Guinea, surrounding islands, and a small area of old-growth rainforest in Australia.
Unlike most birds, cassowary females are far more territorial than the males. Females will viciously attack any female who attempts to encroach into her territory, which can span several “satellite” male territories. During mating season, females will mate with one male, lay her eggs in his nest, and leave for the next male in her territory. In addition to the high energy output of laying the eggs (third-largest of all the birds), this polyandrous behavior allows the female to continue to control her territory while still passing on her genes.
The male both incubates the eggs and cares for the chicks when they hatch, and is much more aggressive than normal when the chicks are young, having even been seen keeping the females away from the nest area.
Cassowaries are one of the few birds that has killed humans outright - though attacks are uncommon, due to their rather secluded habitat, a boy named Philip McClean was killed in 1928, when a cassowary kicked him after he tripped and fell, severing his carotid artery. The bird had been chasing him because he and his brother had decided to try and kill it with clubs after finding it on their property, and probably wouldn’t have touched them if they hadn’t been beating it over the head.
Transactions of the Scientific Meetings of the Zoological Society of London. 1901.
holy crap, gannets are amazing
Gannets hunt fish by diving from a height into the sea and pursuing their prey underwater. Gannets have a number of adaptations which enable them to do this:
- they have no external nostrils, they are located inside the mouth instead;
- they have air sacs in their face and chest under their skin which act like bubble wrapping, cushioning the impact with the water;
- their eyes are positioned far enough forward on their face to give them binocular vision, allowing them to judge distances accurately.
Gannets can dive from a height of 30 metres, achieving speeds of 100 km/h as they strike the water, enabling them to catch fish much deeper than most airborne birds.
Biology, are you fucking serious right now? There’s an order of sharks called Carcharhiniformes, and the shark Carcharodon carcharius isn’t fucking in it?????????? UGH
i would seriously bet $50 that that “gynandromorph” cardinal is just fucking piebald