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 Drafts and withdrawn editions are never mixed into this index.
Along the Mediterranean coast, workers taken from Portugal and from Italy do not fight when introduced to each other. Genetic and behavioural work indicates a single cooperative network running roughly 6,000 kilometres.
Europe's best-known giant skate was described in 1758 and fished to near extinction under a single name. In 2010 it was shown to be two distinct species that had been lumped together, so the animal on the red list had never been assessed properly.
This long-necked antelope of the dry Horn of Africa appears to meet its water needs entirely from the leaves it browses. Observers report no confirmed drinking even where water is available nearby.
The shoulder hump that identifies a grizzly is not fat or bone but a mass of muscle anchoring the forelimbs. It powers the digging that supplies much of the bear's food, and it distinguishes grizzlies from black bears at a glance.
Its range map is not a band along the coast but a handful of separated patches, from the English Channel to Morocco and the western Mediterranean. Local abundance can be high inside a pocket while the gaps between them stay empty.
In deep hibernation a groundhog's core temperature falls to within a few degrees of its burrow, its heartbeat drops from roughly a hundred beats a minute to a handful, and it breathes only a few times a minute. It is not sleeping; it is running a different metabolism.
Satellite tags on Cuvier's beaked whales have logged a dive of 3 hours and 42 minutes off North Carolina, and a separate record depth of 2,992 metres off southern California. Both are the deepest and longest dives recorded for any mammal.
The last widely accepted records of the ivory-billed woodpecker date from the 1940s in Louisiana and the 1980s in Cuba. Later claimed rediscoveries produced no image that convinced the field, and the species' formal status remains contested.
Giant tortoises once lived across the islands of the western Indian Ocean. Sailors ate almost all of them. The survivors are concentrated on a single remote raised coral atoll, where the wild population runs to roughly one hundred thousand animals.
Known from carcasses since the nineteenth century, Architeuthis was never seen alive in its habitat until a Japanese team hooked one on a baited line at about 900 metres and photographed the encounter.
Platydemus manokwari tracks land snails by following their mucus trails, then feeds by everting its pharynx into the shell. It was deliberately introduced to several Pacific islands and has since been implicated in snail extinctions.
Northern Europe is too cool for reptile eggs to develop in bare soil. Grass snakes solve the problem by laying in rotting vegetation, where microbial decay supplies steady warmth, and garden compost heaps are now among their most reliable nest sites.
Botos are born grey and many adults turn pink, but the colour is not evenly distributed. Males are pinker than females, and the pinkest males are those carrying the most bite marks from fights with other males.
The arapaima shares its water with piranhas and wears armour to match. Its scales are layered composites with a hard mineralised outer surface over tough, twisted collagen, and mechanical tests show piranha teeth fracture before the scale does.
The white-tailed eagle was shot out of Britain by the early twentieth century: the last known breeding was on Skye in 1916, and the last bird was killed on Shetland in 1918. Norwegian birds released on Rum from 1975 rebuilt the population.
Silver-haired bats do not use caves. They wedge themselves into the gap between loose bark and the trunk of a standing dead tree, a roost that lasts a season or two, which means the species depends on forests that are allowed to keep their snags.
In the 1990s the common dolphin was divided into short-beaked and long-beaked species on the strength of body shape. Later genetic work showed that long-beaked forms had arisen independently in several regions, and in 2016 they were folded back into one species.
Two rays of the pelvic fins and one of the tail are elongated and stiffened into struts. The fish rests on them above the sediment, facing into the current, and holds its long pectoral fins forward like antennae.
Ancient DNA published in 2021 showed the dire wolf diverged from the lineage leading to grey wolves, coyotes and dogs several million years ago, with no sign of interbreeding. Its resemblance to a grey wolf is convergence, and it has been moved to its own genus.
Its electric organs are stacks of modified muscle cells wired in series, and the discharge is powerful enough to knock down an adult. The weapon and the naval torpedo share a name, and the ray had it first.
After rats wiped out the Lord Howe Island stick insect early in the twentieth century, the species was written off. In 2001 a surviving population of a few dozen individuals was confirmed on Ball's Pyramid, clustered around a single melaleuca shrub.
Canada closed the northern cod fishery in 1992 expecting a two-year pause. More than three decades later the stock remains far below its historical size, and the ecosystem around it reorganised in ways that appear to hold cod down.
The slug's defensive slime contains compounds that produce a numbing sensation on contact with a mouth, and it is so viscous and adhesive that it is difficult to remove. Both properties discourage animals from finishing the meal.
Zanclus cornutus is the sole living member of the family Zanclidae. Its nearest relatives are the surgeonfish, and a distant butterflyfish, the pennant coralfish, carries such a similar banded outline that the two are constantly mistaken for each other.