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 Drafts and withdrawn editions are never mixed into this index.
Radiocarbon dating of proteins in the eye lens, which form before birth and are never replaced, gave a Greenland shark population age range with a most likely maximum near 390 years. It is the longest lifespan established for any vertebrate.
When floodwaters retreat, the plants they graze become unreachable and the manatees are confined to deep lakes. They are thought to live largely on stored fat for months, an unusual strategy for a large aquatic herbivore.
Its hind legs are short for a toad, and it moves across open sand with a quick scurrying run. The gait suits a species that lives on dunes and heath where there is little cover to leap into.
This beetle spends its life underwater but never breathes water. It surfaces tail first, traps a bubble of air beneath the wing cases, and the bubble goes on drawing oxygen from the pond after the beetle submerges.
Water reflects sonar like a mirror, so a submerged fish is acoustically invisible. The greater bulldog bat solves this by reading the small disturbances a fish makes at the surface, then raking the water with its claws where the ripple was.
A young halibut is a symmetrical, upright larva with an eye on each side. During metamorphosis the left eye migrates over the top of the head to join the right, the skull remodels, and the fish tips over to live on its blind side.
There is no vaccine for Dracunculus medinensis and no drug that reliably kills the adult. Human cases have nonetheless fallen from millions a year in the 1980s to fewer than twenty, using water filtration and case containment alone.
Lake Malawi contains several hundred cichlid species, the great majority found nowhere else on Earth. Genetic evidence indicates that this entire flock descends from a small founding stock within roughly the past one to two million years.
Male carpenter bees patrol nest entrances and rush at anything that passes, which reads as aggression. A sting is a modified egg-laying organ, so no male bee of any species possesses one at all.
Its tusks are not digging tools in the way often described. The walrus ploughs the seabed with its snout and stiff whiskers, then seals its lips around a clam and pulls the soft body out with a piston-like tongue, leaving the shell behind.
A sockeye cannot make red pigment. It accumulates carotenoids from the krill and other crustaceans it eats at sea, stores them in muscle, and then moves them into skin and eggs as it ripens for spawning, leaving the flesh paler.
Under ice, in mud where dissolved oxygen runs out, an adult painted turtle can go months without oxygen. It survives by shutting down almost all activity and using its own shell to neutralise the acid that anaerobic metabolism produces.
Cymothoa exigua enters a fish's mouth through the gills, severs the blood supply to the tongue until it withers, and then attaches in its place. The fish appears to use the parasite's body as a working substitute tongue.
These pelicans do not dive. Groups swim abreast in a line or horseshoe, beating the water with their wings to drive fish into the shallows, then dip their pouches in near unison. The pouch is a scoop and a strainer, not a storage bag.
In June 2022 fishers on the Mekong in Cambodia landed a female giant freshwater stingray weighing about 300 kilograms and roughly four metres long. It was tagged and released, and stands as the heaviest freshwater fish ever documented.
Male palm cockatoos snap off a stick or seed pod, trim it, and beat it against a hollow trunk in a regular rhythm. Individual males keep recognisable tempos, making this the clearest case of instrumental music outside humans.
A walking eland produces a sharp clicking sound carried well across open ground. The click comes from the animal's forelegs, and its pitch is lower in larger bulls, making it an honest signal of size heard before the animal is seen.
Trained dogs and mongooses that readily find other snakes by smell repeatedly failed to detect motionless puff adders in controlled trials, suggesting the species suppresses the odour cues that predators and prey rely on.
Bone makes up the large majority of the bearded vulture's diet, an arrangement unmatched among birds. It carries marrow bones aloft and drops them onto rock to shatter them, then swallows fragments that its extremely acidic stomach dissolves.
Hunted for hides and shot as competition for livestock, the black wildebeest was reduced by the end of the nineteenth century to a small remnant of fewer than six hundred animals on a handful of farms. Every animal alive today descends from that bottleneck.
Nearly all parrots lay in a hole. The monk parakeet instead weaves bulky communal nests of thorny twigs, with separate chambers for separate pairs, and the structures can persist and grow for years.
The Lyme bacterium lives in a tick's midgut and must migrate to the salivary glands before it can be passed on. That relocation takes time, which is why the risk from a blacklegged tick rises sharply after roughly a day and a half of feeding.
A plaice adjusts its pattern to the ground beneath it by redistributing pigment inside skin cells called melanophores. Vision drives the response, so a blinded flatfish cannot match the substrate, and the orange spots persist through the change.
An Adélie nest is a scrape lined with pebbles, and pebbles are scarce. Birds carry them one at a time, and a great many are taken from neighbouring nests while the owner is looking elsewhere, which is why colonies are full of small local disputes.