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 Drafts and withdrawn editions are never mixed into this index.
Most animals leave a burning forest. Melanophila acuminata flies in, because its larvae can only develop in freshly killed conifers, and it finds the fire using infrared receptors on its thorax.
Peccaries belong to a separate American family from the pigs of Eurasia and Africa, with straight tusks, fewer hind toes and a complex stomach. In the Sonoran Desert they chew prickly pear pads whole, spines and all.
A century of bounties, poisoning and shooting coincided with the coyote spreading across the continent, into eastern forests and into cities. Removing wolves opened the ground, and coyote reproduction responds to heavy mortality by increasing.
The pedal disc that looks like glue is muscular. Anemones creep across rock at rates measured in centimetres per hour, detach and drift, and some somersault or swim in bursts to escape a predatory sea star.
A chigger does not burrow under the skin and does not feed on blood. It attaches at the surface, injects enzymes that liquefy skin cells, and drinks the resulting slurry through a hardened feeding tube that the body's own response helps build.
An adult Riftia pachyptila carries no mouth and no gut. Instead it houses a dense colony of chemosynthetic bacteria in a specialised internal organ, and feeds on the organic compounds those bacteria manufacture from hydrogen sulphide.
Its grooved venom fangs are set beneath the eye rather than at the front of the mouth, an arrangement long assumed to make the snake harmless to humans. A herpetologist's death in 1957 corrected that assumption.
Despite its name and its scientific epithet meaning light-shunning, this salamander is not a true cave animal. It concentrates in the twilight zone near entrances, where insects are available, and it retains full eyes and bright colour.
The bearded seal's breeding call is a warbling trill that sweeps downward in frequency for up to a minute, audible to hydrophones tens of kilometres away and distinctive enough that individual males can sometimes be told apart by their song.
A bandicoot embryo spends about twelve and a half days in the uterus before birth. That was long taken as the shortest mammalian gestation on record, until the stripe-faced dunnart was measured at around eleven days. The newborn is the size of a grain of rice and finishes developing in the pouch.
Between eye and nostril, a pit viper carries a membrane suspended in a chamber, richly supplied with nerve endings tuned to heat. Signals from it merge with vision in the brain, letting a rattlesnake strike accurately in total darkness.
Breeding females in a group frequently deliver within hours of each other, and the pups are raised in one communal litter. The synchrony makes it hard for any adult to tell which pups are hers, which appears to be the point.
Growth-band and radiocarbon-based ageing has produced estimates well over a century for large individuals, with little sign of the physical decline that age usually brings. The exact ceiling remains an estimate rather than a count.
Moths hear bat sonar and evade it. Townsend's big-eared bat counters by calling very quietly, roughly a hundred times fainter than a loud aerial hawker, and by using enormous ears to recover the faint echoes that come back.
Records for the longest insect depend on how it is measured. Chan's megastick, from Borneo, has a body a little over 35 centimetres and a total length above half a metre with the forelegs extended, but a Chinese species described later measures longer still.
The candiru's reputation rests on a claim that it follows a urine stream into the human urethra. Controlled tests found no attraction to urine or ammonia, and the fish appear to locate their host fish by sight rather than by chemical cue.
A female lays two eggs several days apart, but the younger chick has died in effectively every recorded wild nest. The second egg functions as insurance, and conservation programmes remove it and hand-rear the chick.
Pere David's deer had already vanished from the wild when a French missionary described it in 1866 from animals in an imperial hunting park near Beijing. The species now living traces to a handful taken to Europe before the park herd was destroyed.
Preserved specimens show a front horn that is broad and flattened side to side rather than round in cross section, with wear on its leading face. The pattern matches the sideways sweeping motion a grazer would use to clear snow from winter forage.
Rather than avoiding ice, this alpine insect tolerates it. Ice forms in the spaces between its cells during winter and the animal is stiff and immobile, then thaws and resumes activity, a strategy that can repeat many times in a season.
Facing winters cold enough to freeze surface water, this alligator excavates tunnel systems with chambers, air holes and multiple entrances, and spends roughly half the year underground in a dormant state.
Medieval European writers held that barnacle geese hatched from goose barnacles growing on driftwood, because nobody had found the birds' nests. The barnacle kept the name; the goose kept the name; the theory was wrong in both directions.
First-instar nymphs are black with a red head and run in a quick, jerky, ant-like manner quite unlike the slow adults. The eggs are collected by ants, and the hatchlings leave the nest before the resemblance stops being useful.
Spawning male haddock produce sound by contracting specialised muscles against the swim bladder, generating knocks that speed into a hum. The tempo rises as courtship proceeds, and the sound is part of how a female is brought to spawn.