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 Drafts and withdrawn editions are never mixed into this index.
A breeding pair of golden eagles may hold a home range spanning tens of square kilometres, and in poor upland habitat considerably more. The territory is defended by conspicuous undulating display flights rather than by constant physical combat.
Despite the build and the habit of bounding away from predators, the impala sits alone in its own genus and tribe. Its closest relatives are not gazelles but the larger antelopes, and only males grow horns.
Great tinamou eggs are a saturated turquoise-blue with a hard, glossy surface shared across the tinamou family and matched by no other birds. They are laid on the open forest floor, which makes their conspicuousness genuinely puzzling for a ground-nesting bird surrounded by predators.
On Kangaroo Island and other offshore populations without permanent fresh water, tammar wallabies have been recorded drinking seawater and surviving on it. Their kidneys concentrate urine strongly enough to make the salt load a net gain.
The mimic filefish reproduces the pattern of the black-saddled toxic puffer closely enough to fool predators and divers. It has no toxin of its own; the giveaway is the dorsal fin and the number of fin spines.
Most bat echolocation sits well above the range of human hearing. The spotted bat calls at frequencies low enough that many people can hear it as a sharp metallic click overhead, an adaptation that appears aimed at moths.
A sloth bear is missing its upper central incisors, leaving a permanent gap. It closes its nostrils, digs open a termite mound and sucks the insects through that gap with a noise audible from well over a hundred metres away.
Instead of an open cup in a branch, the ovenbird constructs a domed nest on the forest floor with the entrance at the side, roofed and camouflaged with leaf litter so that it disappears into the surrounding ground.
A grey squirrel buries nuts one at a time across hundreds of separate spots. It recovers many by spatial memory, but the ones it misses germinate, which makes the squirrel an accidental but significant disperser of oak and hickory.
Squid have an escape nerve fibre up to a millimetre across, hundreds of times wider than a typical vertebrate axon. Electrodes could be pushed inside it, which is how the action potential was finally measured.
On the floor of the turtle's open mouth sits a small pink appendage that it can wriggle. To a fish looking in, it reads as a worm. The turtle lies still, works the lure, and closes when the fish enters.
Schneider's dwarf caiman often sites its nest mound against or partly around a termite nest. Termite metabolism keeps the mound warm, supplying incubation heat in shaded rainforest where decomposing vegetation alone may not be enough.
A returning forager walks a figure-of-eight on the vertical comb, waggling along the central run. The angle of that run from vertical gives the bearing relative to the sun; its duration gives the distance to the food.
The male's long neck is used to fight rivals, but the female's shorter one is a tool. She scores a leaf, folds it in stages and rolls it into a tight tube containing a single egg, then cuts the tube free.
Great whites are regional endotherms. A lattice of intertwined arteries and veins traps the heat their swimming muscles generate, holding the core of the body several degrees above the surrounding water and letting the shark hunt in cold seas.
A red velvet mite begins as a six-legged parasitic larva clinging to a grasshopper or beetle, drinking its fluids. After moulting it becomes an eight-legged free-living predator that eats insect eggs and small arthropods in the soil.
Brine shrimp produce cysts that enter cryptobiosis, a state with no detectable metabolism. Dried, the cysts survive years of desiccation, freezing and vacuum, and hatch within a day of being returned to salt water.
Rather than sweating to stay cool, a gemsbok can allow its core temperature to rise well above normal during the hottest hours, storing heat instead of spending water, then shedding it at night.
The maned wolf eats about as much plant matter as animal prey, and one fruit in particular. The tomato-like lobeira, sometimes called the wolf apple, appears constantly in its scat, and the animal is a major seed disperser for it.
Bonobos occur only south of the Congo River and chimpanzees only north of it. Neither ape swims well, and the river's great width and current appear to have kept the two lineages apart for something over a million years.
Grinding a morpho's wing to powder yields brown dust. The colour comes from layered ridges on the wing scales that cancel most wavelengths and reflect blue, which is why the shade shifts with viewing angle.
Migratory tree bats die at wind facilities in numbers that outstrip resident cave species by a wide margin. The reason is not that turbines are hard to detect: evidence suggests the bats are attracted to the tall structures rather than blundering into them.
In 2003 a banteng calf was born from a skin cell frozen in 1980, carried by a domestic cow. It was among the first endangered mammals cloned from long-stored tissue, and it lived for several years.
The coiled sand cast on a beach is one end of a U-shaped burrow. A few centimetres away sits a shallow funnel marking the head shaft, where the worm draws sediment down and feeds beneath the surface.