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 Drafts and withdrawn editions are never mixed into this index.
Charles Darwin collected ground sloth fossils in Argentina during the Beagle voyage. The presence of enormous extinct relatives of small living South American sloths and armadillos in the same region became a key observation in his thinking about descent with modification.
Tomato, blueberry and nightshade flowers keep pollen sealed inside tubular anthers that open only at a tiny pore. A bumblebee grips the anther and vibrates her flight muscles without flying, and the pollen shoots out.
For most running animals, going faster costs more energy per unit distance. In red kangaroos over a broad range of speeds the metabolic cost stays remarkably flat, because elastic tendons in the hind legs recycle energy from stride to stride.
A blue mussel anchors itself with byssal threads tipped with an adhesive plaque that bonds to wet, salted, surf-battered rock. The chemistry behind it, built around the amino acid DOPA, is what most industrial adhesives cannot do.
Boxfish secrete ostracitoxin from their skin when severely stressed or dying. In the open sea it disperses harmlessly, but in an aquarium the released mucus can kill every fish present, including the boxfish itself.
Japanese macaques on Koshima really did learn to wash sweet potatoes, starting with one young female in 1953. The famous claim that the habit leapt to distant islands once a hundred monkeys knew it was invented decades later and contradicts the field notes.
Naturalists first documented the animal in 1741, when a shipwrecked expedition ate it to survive. The last credible record is 1768. Its extinction is one of the fastest on record for a large mammal known to science.
Every Pacific salmon dies after spawning. The Atlantic salmon does not necessarily: a minority of spawned-out fish, called kelts and overwhelmingly female, drop back downstream, recondition at sea, and return to the river to spawn again.
An elephant's trunk is a muscular hydrostat: a boneless, jointless organ that changes shape by redistributing incompressible tissue. It can uproot a small tree and also pick up a single seed, and it doubles as the animal's nose.
Tagging in the North Atlantic has followed individual blue sharks from the eastern seaboard of North America to Europe and Africa, with movements of several thousand kilometres. The species is the most widely distributed shark in the world.
Northern water snakes are killed year after year as venomous cottonmouths, in places where cottonmouths do not occur at all. The two differ in head shape, pupil, swimming posture and range, and the range difference alone settles most cases.
Most North American songbirds nest in May and June. The American goldfinch typically begins in late June or July, timing its brood to the seeding of thistles and other composites that supply both nest lining and nestling food.
Underground fungi make up most of the long-nosed potoroo's diet. The spores survive its gut and are deposited in droppings across the forest floor, seeding the mycorrhizal partnerships that eucalypts depend on for nutrients.
A bacterium that domestic sheep carry harmlessly can sweep through a bighorn herd and kill much of it within a season. The population then stalls for years, because the lambs born afterwards keep dying before their first winter.
The reddish fluid on a hippo's skin is not blood and not sweat. It is a secretion containing two unstable pigments that absorb ultraviolet light and inhibit bacterial growth, produced by glands in the animal's hairless hide.
Males reach around 17 centimetres, a figure often quoted as proof of enormous bulk. More than half of that measurement is the thoracic horn, a hollow extension of the pronotum that carries no body mass to speak of.
The common krait enters houses at night hunting rodents and other snakes, and often bites someone sleeping on the floor. The bite can be nearly painless, so the first sign is paralysis hours later, sometimes mistaken for another illness.
At a few beaches, olive ridley females come ashore together in tens or hundreds of thousands across a few nights. The crowding is so dense that later arrivals dig up the nests of earlier ones, destroying a large fraction of the eggs.
Insects colonised almost everything except the sea. The exception is Halobates, a group of water striders that spend their whole lives on the surface of tropical oceans, hundreds of kilometres from any coast, and lay eggs on floating debris.
Whales landed in Alaska in the twentieth century were found with stone and ivory harpoon tips embedded in their blubber, weapons abandoned by the 1880s. Chemical dating of eye lenses later put some individuals past two hundred years old.
Southern cassowaries swallow large fruit whole and carry the seeds for kilometres before passing them intact. For a number of rainforest trees with fruit too big for any other Australian animal to swallow, the cassowary is effectively the only disperser left.
In United States labelling practice, white meat tuna refers to one species. Albacore's flesh is markedly paler than that of other commercial tunas, and the term is reserved for it; other species must be sold as light or dark tuna.
The last bucardo died in 2000. In 2003 a cloned kid was born from her preserved cells, briefly returning the subspecies to existence. The clone died of a lung defect within minutes, making it the only known animal to become extinct on two occasions.
A porcupine's quills protect its back and tail but not its head. Fishers circle in front of one, deliver repeated bites to the unprotected face, and only then turn the exhausted animal over.