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 Drafts and withdrawn editions are never mixed into this index.
Its spines are short and blunt. The hazard comes from the pale blossoms covering its surface, which are pedicellariae: tiny stalked jaws that clamp onto skin, detach, and keep injecting venom after the urchin has gone.
A mating pair climbs to an overhang, lowers itself on a single thick strand of mucus, and entwines in mid-air while everting translucent blue reproductive organs. Both animals are hermaphrodites and both can be inseminated.
Draco lizards do not have wings built from limbs or skin flaps along the flanks alone. Five to seven elongated ribs on each side swing outward and stretch a membrane called the patagium, which the lizard steers with its forelimbs.
Under the wing cases of a harlequin beetle, small pseudoscorpions ride between dying trees. They do not feed on the beetle. They mate, compete and give birth in the space beneath its elytra during the flight.
Anopheles gambiae was described as one mosquito and is now understood as a complex of closely related species that cannot be told apart reliably by eye. They differ in where they breed, whom they bite and how well they transmit malaria.
Most snakes abandon their eggs. Seven years of fieldwork in South Africa found female southern African pythons, a close relative of the African rock python and long treated as the same species, staying with their hatchlings inside the nest burrow for about two weeks.
The bald uakari's scarlet face comes from blood in skin with almost no pigment, not from a red dye. Malaria and other blood parasites make the face pale, so the colour reads as a visible health certificate to potential mates.
When a large empty shell appears on a shore, hermit crabs gather and line up by size. The biggest crab moves in first, and each smaller crab takes the shell just vacated, so a single new shell can rehouse a dozen animals in seconds.
The geography cone releases a cloud of specialised insulin into the water around a fish, crashing its blood sugar and leaving it too sluggish to flee. The venom is used before the harpoon strike, not after it.
Female Nile tilapia collect fertilised eggs into the mouth and hold them there through hatching, not feeding for a week or more. Even after release the fry rush back inside when threatened, which is why aquaculture handles broodstock separately.
A specimen washed ashore in Scotland in the 1860s was reported at over 50 metres, which is often cited as making Lineus longissimus the longest animal on record. The figure comes with a large caveat about how nemerteans stretch.
Between its two thin cell layers sits mesoglea, a jelly of water held in a protein and sugar mesh. A stranded moon jelly on a beach effectively evaporates, leaving a film that is a small fraction of the animal's original volume.
The tall casque on a veiled chameleon's head is not only a display structure. Condensing dew and mist run down its channelled surface toward the mouth, giving an animal from arid Yemeni highlands a way to drink without standing water.
The purple frog spends its life in deep burrows eating termites through a groove in its mouth. It emerges to breed during the first monsoon rains, which is why a large Indian frog went undescribed until 2003.
In 1822 a white stork was shot in Germany carrying a long African spear through its neck. It had flown home wounded, and the arrow it carried settled centuries of speculation about where Europe's birds went in winter.
Gecko toe pads carry millions of hair-like setae, each splitting into hundreds of flattened tips. Contact at that scale brings enormous surface area within range of van der Waals forces, the weak attraction between molecules, which is what holds the animal to glass.
The soft yellow cloth sold for drying cars takes its name from this alpine animal, whose skin was once oil-tanned for the purpose. Almost all of it is now made from sheepskin, and the connection survives only in the word.
The oilbird produces bursts of audible clicks and uses the returning echoes to move through pitch-dark caves. Its echolocation is coarse compared with a bat's: in the classic experiment birds dodged discs about twenty centimetres across and flew straight into smaller ones.
For decades the redknee sold worldwide was labelled Brachypelma smithi. A 2017 revision showed that the animals in trade were mostly a separate species, Brachypelma hamorii, with the true smithi confined to a different part of Mexico.
A male house wren fills multiple cavities in his territory with stick foundations before any female arrives. She inspects them, selects one and finishes it herself. The surplus nests occupy cavities that rivals might otherwise use.
Sharks lack the bony structures used to age other fish. Researchers instead radiocarbon-dated the metabolically inert core of the eye lens, which forms before birth, and found lifespans measured in centuries.
Most global bird spreads are the work of people moving birds. The cattle egret crossed the Atlantic under its own power, appearing in South America in the 1870s and then working north to reach Canada within a century.
Scarlet ibis chicks are dull grey-brown and only become red as they mature on a diet heavy in crabs and other crustaceans. The carotenoids in that prey, concentrated over months, produce a deep and uniform red.
Most animals that run out of food simply lose weight. Antarctic krill do something stranger: they moult into a smaller body, reversing growth over successive sheds, and can return to a juvenile size before regrowing when food returns.