The odd mechanics of living things, by Maren.
Sorted newest first.
The American dipper Cinclus mexicanus is a songbird that walks on stream beds underwater hunting aquatic insects. It is the only songbird that does this. The adaptations are subtle, the textbook account is mostly right, and the open questions are about underwater sensing.
Kiwa hirsuta and its relatives live at hydrothermal vents and farm chemosynthetic bacteria on dense setae covering their claws. The bacteria oxidize sulfide and methane; the crabs wave their claws in vent fluid to feed them. Cultivation, not capture.
The Australian superb lyrebird Menura novaehollandiae produces 15-30 minute songs containing accurate reproductions of dozens of native bird species plus mechanical sounds that entered the species vocabulary in the last century. The mechanism and the cultural transmission puzzle.
Anoura fistulata is a small bat from the Ecuadorian Andes with a tongue 150 percent of its body length, the highest tongue-to-body ratio of any mammal. The tongue retracts into the chest cavity through a specialized housing.
Some bacteria grow magnetic crystals inside membrane vesicles, aligned with Earth's field. The crystals form in specialized compartments smaller than a virus, with shape and size controlled at the nanometer scale by a process nanotechnology cannot match.
Mole crickets sing from inside a Y-shaped burrow whose geometry acts as an exponential horn matched to the singer's wing frequency. The result is one of the loudest insect calls on Earth produced by a 3-centimeter animal in a 30-centimeter underground excavation.
Common cuckoos lay eggs in nests of host species that raise the chick at the cost of their own brood. Hosts evolve egg recognition to reject parasites. Cuckoos evolve egg mimicry to defeat the recognition. One of the cleanest cases of measurable coevolution in vertebrate biology.
Sailfish coordinate group hunts on sardine schools using sail-display signaling and turn-taking attacks. The cooperation is more sophisticated than canonical fish-cognition accounts anticipated and was only characterized in the 2010s.
The honey possum is one of the few mammals to subsist entirely on nectar and pollen. Its specialization is so extreme that it cannot survive outside the few hundred plant species that flower in sequence across southwestern Australian heath.
The pistol shrimp is famous for its acoustic stun mechanism. The sensory side of the same animal — how a 5-gram crustacean with a few hundred thousand neurons targets prey accurately enough for the 0.6-millisecond claw release to land — has been characterized much more recently.
Box jellyfish have twenty-four eyes arranged in clusters around the bell, including pairs that look much like camera-style vertebrate eyes with lens and retina. The species has no brain to process the visual information, and the question of how it uses what its eyes see is genuinely strange.
The goblin shark lives in deep ocean water below 200 meters and has a jaw mechanism that can launch forward at striking speeds documented at over 3 meters per second. The mechanism has no close parallel among other sharks and was only directly observed on video in the last decade.