Field notebook
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Field notebook
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Permanent editions
Published facts keep their original date, evidence and correction trail. Drafts and withdrawn editions are never mixed into this index.
Anatomists long placed the false gharial among the true crocodiles and treated its narrow snout as convergence. Molecular data reversed that, showing it is the closest living relative of the gharial, and the name has aged into an irony.
The underside of a spider monkey's tail tip is hairless and covered in friction ridges arranged in whorls and loops, like the pads of a hand. The pattern is unique to the individual, so a tail leaves a print of its own.
The pale spots behind a whale shark's gills form a pattern that stays stable for life. Researchers identify individuals from photographs using an algorithm originally written to match star fields in astronomical images.
The sword-billed hummingbird is the only bird whose bill is longer than the rest of its body, tail excluded: about 8 to 12 centimetres of it. The bill cannot reach most of the plumage, so the bird preens with its feet instead.
A male Caribbean reef squid positioned between a female and a rival can display courtship colouration on the side facing the female and aggressive colouration on the side facing the rival, simultaneously.
It sits in the hedgehog family Erinaceidae, among the gymnures or hairy hedgehogs, and carries coarse fur instead of quills. Its defence is chemical: a pungent, ammonia-like scent marked along its trails.
In high mountain lakes where summers are short and the land offers little, alpine newt populations sometimes stop metamorphosing. Adults keep their gills and breed in the water, in the same species that transforms normally at lower elevation.
Its egg is a leathery cone wound with a helical flange, like a large screw. The female is thought to wedge the freshly laid, still-soft case into a rock crevice, where it hardens and becomes very difficult for a predator to remove.
A geoduck's siphon and body are far larger than the two valves that are supposed to protect them. Instead of closing up, the clam relies on depth, burrowing a metre into sediment and staying there for a century or more.
Brassicas defend themselves by converting glucosinolates into toxic isothiocyanates the moment tissue is damaged. Cabbage white caterpillars carry a gut protein that redirects the reaction to a harmless product, turning a defence into a food supply.
The female transfers eggs into the male's pouch, where he fertilises them and then supplies oxygen, regulates salinity, and provides nutrients through a vascularised lining before giving birth. This is more than carrying eggs.
A sugar glider's membrane provides the lift, but the long bushy tail does the steering. Small movements of the tail act as a rudder and trim tab, letting the animal turn and adjust its angle mid-glide.
The green male and the red-and-blue female differ so completely that eighteenth-century naturalists catalogued them as unrelated birds, naming each in turn. They were still treated as two species until the early twentieth century, when the pairing was settled by watching them breed.
Vine snakes have horizontal keyhole-shaped pupils and a narrow groove running along each side of the snout, so both eyes can look forward past the head. The arrangement gives an unusually wide overlap of visual fields for a snake.
All Ornithoptera, Troides and Trogonoptera species are listed under CITES, even common ones like Troides helena. The listing is not because each is rare but because birdwings are hard to tell apart in trade.
A grenadier does not have the fan-shaped tail most fish carry. The body simply tapers to a point, with the dorsal and anal fins running along it, so the fish swims by rippling a long tapering rear half.
Genetic work on mummies and museum specimens showed that the crocodile most often kept in temples and mummified in ancient Egypt was not the Nile crocodile but a separate, smaller and more tractable species, formally recognised in 2011.
Human Rh-positive and Rh-negative blood types take their name from the rhesus macaque, because the original 1940 antibodies were raised against monkey red cells. Later work showed those antibodies were detecting a different antigen, but the name was never corrected.
Almost all European tits take over existing cavities. The willow tit chisels a fresh chamber into soft, decaying wood each year, which ties the species to dead standing timber that tidy woodland management removes.
Pithecophaga jefferyi means monkey-eater, from early accounts of the bird taking macaques. Later study showed its usual prey is the Philippine flying lemur, along with civets, snakes and other birds; monkeys are a minor item.
The long-legged fly bumping against a lit window is routinely described as the most venomous spider or a mosquito the size of a thumb. It is neither. Most adult crane flies cannot bite, and none carry venom capable of harming a person.
Sunfish lying flat at the surface look idle. Tagging shows they are recovering from repeated dives into cold water hundreds of metres down, where they feed, and the basking is part of a thermoregulatory cycle.
Adults commonly run four to six metres, and specimens beyond seven are notable. A ten-metre snake reported from Sulawesi early in the twentieth century is still widely repeated, but the measurement was never preserved, and skins stretch, so snake length records run long.
During the autumn rut a red deer stag pulls its larynx almost to the breastbone. The move lengthens the vocal tract, drops the resonances of the roar, and makes the caller sound like a larger animal than it is.