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 Drafts and withdrawn editions are never mixed into this index.
Nightingales sing round the clock, but the celebrated nocturnal song has a narrow purpose. Males that have not yet attracted a mate do most of the singing through the dark hours; once a female settles with them, night singing usually falls away or stops.
An Indian flying fox does not swallow fruit. It presses the pulp against the roof of its mouth with its tongue, swallows the juice, and drops the compressed fibre and larger seeds as small dry pellets called ejecta.
The northern white rhinoceros is functionally extinct. Its last male died in 2018, leaving a mother and daughter who cannot carry a pregnancy, and any future depends on stored eggs, frozen sperm and a surrogate of another subspecies.
Because a cricket's muscles run at ambient temperature, its song speeds up in warm air and slows in cool. Counting chirps over a fixed interval gives a usable estimate of temperature, a relationship first quantified in the 1890s.
The red belly that gives this bird its name is a faint pinkish wash rarely visible in the field. The obvious red is on the crown and nape, but that name was already taken by the red-headed woodpecker, so the belly won.
A pill millipede and a pill woodlouse look nearly the same rolled up, but one is a myriapod and the other a crustacean. Counting legs per segment separates them: millipedes carry two pairs on most segments, woodlice one.
Handled or threatened in the nest, European roller nestlings produce a foul orange fluid. The secretion deters predators, and returning parents appear to read its smell as a warning that the nest has been disturbed.
Tasmania was joined to mainland Australia until Bass Strait flooded around twelve thousand years ago. The emus stranded on the island diverged into a smaller island form, then disappeared within a few decades of European settlement.
A Japanese spider crab can span more than three metres from claw to claw, yet its body would fit inside a bicycle helmet. Almost the entire record belongs to eight spindly walking legs and a pair of very long chelipeds.
The bright red juvenile red salamander closely resembles the toxic red eft of the eastern newt, and experiments with captive birds suggest predators that have learned to avoid efts also avoid the harmless mimic.
DDT metabolites thinned pelican eggshells until eggs broke under the incubating parent, and the species vanished from Louisiana entirely. After the pesticide was banned in the United States in 1972, populations rebuilt, and the bird was removed from the endangered species list in 2009.
An assassin bug has no jaws to chew with. It stabs prey with a hinged beak, injects saliva that paralyses the victim and dissolves its tissues from within, then draws the liquefied contents back out through the same tube.
The resemblance is not a coincidence of description. Binturong urine contains 2-acetyl-1-pyrroline, the same compound that gives popcorn, jasmine rice and fresh bread their characteristic aroma, and the animal spreads it along branches as it moves through the canopy.
An elephant bird egg could hold about thirty centimetres of length and a volume of roughly eight to nine litres, more than a hundred chicken eggs and larger than any dinosaur egg yet found. Intact shells still turn up in Madagascar's coastal dunes.
A bilby digs constantly, and a forward-facing pouch would fill with soil within minutes. Its pouch opens towards the tail instead, which keeps the young clean while the mother excavates.
Giant pandas digest bamboo using a short, simple digestive tract built for meat, with no rumen and no lengthy fermentation chamber. They extract only a small fraction of the available energy and make up the shortfall by eating for most of the day.
Eastern indigo snakes shelter and overwinter in burrows dug by gopher tortoises. Protecting the snake therefore means protecting a reptile that does not resemble it at all, and the pine habitat that supports both.
The species maintains cohesive territorial packs that patrol and rest together, yet each animal forages by itself, stalking rodents across open grassland. The pack exists for territory defence and pup rearing, not for bringing down prey.
Almost every mammal carries disc-shaped red blood cells. Camels, guanacos and their relatives carry small elliptical ones that resist swelling and bursting, part of a blood chemistry suited to thin air and unreliable water.
Selected workers are fed until the abdomen swells to the size of a grape and the plates of the exoskeleton are pushed apart. They hang immobile from a chamber ceiling and regurgitate on demand for months.
Male euglossine bees scrape fragrance compounds from orchids, rotting wood and fungi, then pack the mixture into hollow chambers in their swollen hind legs. The blend is not food and not for the nest.
Along with the paired pelvic claspers shared with sharks and rays, a male chimaera has a retractable, spine-tipped club on top of its head. It folds into a pocket between the eyes and is used to grip the female during mating.
Genetic analysis of ancient and modern cattle points to domestication from a limited number of aurochs females in the Near East around 10,500 years ago. The entire taurine lineage, hundreds of millions of animals, traces to that narrow beginning.
Most amphibians make one crossing from water to land. The eastern newt makes two: larvae metamorphose into a bright orange land-dwelling eft that wanders the forest for years, then returns to the pond and becomes aquatic again as an adult.