Field notebook
Opening the requested public page…
Field notebook
Opening the requested public page…
Permanent editions
Published facts keep their original date, evidence and correction trail. Drafts and withdrawn editions are never mixed into this index.
The scaly-foot snail incorporates iron sulphide minerals into the scales on its foot and into the outer layer of its shell. No other animal is known to build a skeleton with these compounds, and it happens only at vents rich in dissolved iron.
A pike's lunge is not spring-loaded. Measurements of northern pike fast-starts put power output close to the theoretical ceiling for vertebrate muscle, which is the point: the speed comes from a large block of white muscle, a straight body and fins set far back.
A female Dermatobia hominis does not approach the host at all. She catches a mosquito or another blood-feeding fly in flight, glues her eggs to its underside and releases it. The eggs hatch when the courier lands on warm skin.
Too small to walk far and unable to fly, pseudoscorpions disperse by clamping a pincer onto the leg of a fly, beetle or harvestman and riding until the carrier lands somewhere new. The behaviour is called phoresy.
A locust swarm looks purposeful, but its direction is set largely by the prevailing wind. Downwind drift tends to carry swarms towards convergence zones where air masses meet, which are also where rain falls and vegetation grows.
Despite weighing as much as a leopard, the puma belongs to the purring cats. It has a fully ossified hyoid and lacks the specialised vocal folds of Panthera, so its loudest calls are screams and whistles rather than roars.
Thirteen deaths were recorded from Sydney funnel-web bites before an antivenom became available in 1981. None has been recorded since, even though bites and the spiders themselves are no less common in the city's suburbs.
Most songbirds sing hard at dawn and taper off. The red-eyed vireo keeps going through midday heat, and a single male tallied by an observer through one day was recorded delivering more than twenty thousand song phrases.
In the early 1940s the entire wild migratory population of whooping cranes was down to about fifteen birds. All wild whooping cranes alive today trace back to that remnant, which is why the species carries so little genetic diversity.
The smooth snake is confined in Britain to a few heaths in Dorset, Hampshire and Surrey. Its decline tracks the loss of lowland heath almost exactly, because the snake needs mature heather structure and the lizards that live in it.
It is a goat-antelope, closer to the chamois and the serows of Asia than to the genus Capra. Its climbing depends on hooves built like two-part clamps, with a hard outer rim around a soft rubbery pad.
Almost all pelagic marine fish release buoyant eggs that drift. Herring do the opposite: they spawn dense adhesive carpets on gravel and stones, layers deep, which ties the population to particular patches of seabed.
Xylem sap is almost pure water with a trace of amino acids, and it sits under tension inside the plant. A sharpshooter must pump extraordinary volumes through its gut simply to obtain enough nitrogen, and it ejects the surplus in a fine jet.
The female swallowed her fertilised eggs and raised the tadpoles inside her stomach for weeks, suppressing digestion entirely. Both species were extinct within roughly a decade of being described.
The mallard is not just abundant, it is genetically infectious. Wherever it has been introduced or has spread, it hybridises with local ducks such as the Hawaiian koloa and New Zealand's grey duck, producing fertile offspring that blur the parent species.
Bobcats hold territories inside and around large American cities, moving through canyons, culverts and greenbelts. Long-running studies in the Los Angeles area have tracked them across freeways, and found that rat poison rather than traffic is a major cause of illness.
A pair of burying beetles finds a dead mouse, buries it, strips the fur, coats it in secretions and shapes it into a ball. Both parents then stay underground and feed regurgitated carrion to the begging larvae.
The industrial melanism story is old, but its genetic cause was pinned down only in 2016: a transposable element inserted into a single gene. Dating the insertion placed it in the early nineteenth century, matching the historical record.
By the 1970s hide hunting had reduced this crocodile to scattered remnants, and it was listed on the strictest CITES appendix. Sustained protection worked: it now carries a Least Concern assessment, and is one of the few crocodilians to have been formally downlisted.
The six hard projections on the female's abdomen are usually described as defence against birds and wasps. The idea is reasonable and widely repeated, but direct experimental support for it is thin.
Mountain gorillas are the only great ape population known to be growing, passing one thousand animals in the 2018 census. Their own species is still listed as Critically Endangered, because the other eastern gorilla subspecies has collapsed.
The thylacine looked strikingly like a wolf, but it was a marsupial that carried its young in a pouch. Placental dogs and this marsupial carnivore last shared an ancestor well over one hundred million years ago, making the resemblance one of the clearest cases of convergence in mammals.
Swallowed Ascaris eggs hatch in the intestine, but the larvae do not stay. They burrow into blood vessels, pass through the liver and heart to the lungs, climb the airway and are swallowed a second time before maturing.
An adult bee hummingbird weighs roughly two grams and measures about six centimetres from bill tip to tail. Its eggs are around the size of a coffee bean, and the whole nest fits comfortably inside a bottle cap.