Animals such as foxes can smell their prey even when it is concealed under 2 feet (61 cm) of snow or earth.
Many predators have acute hearing, and some such as echolocating bats hunt exclusively by active or passive use of sound.
Large prey may prove troublesome for a predator, while small prey might prove hard to find and in any case provide less of a reward.This has led to a correlation between the size of predators and their prey. For example, adult elephants are relatively safe from predation by lions, but juveniles are vulnerable.Competition is directly evident in intraguild predation, where predators kill and eat predators of competing species at the same trophic level.For example, coyotes compete with and sometimes kill gray foxes and bobcats.Unlike typical parasites, they always kill their hosts, but often not instantly.
Parasitoid wasps are solitary insects that live a free life as adults, laying eggs on or in other insects such as lepidopteran caterpillars.
Many have sharp claws and jaws to grip, kill, and cut up their prey.
In ecology, predators are heterotrophic, getting all their energy from other organisms.
Animals may also be 'grazed' upon by blood-feeding micropredators.
These include annelids such as leeches, crustaceans such as branchiurans and gnathiid isopods, dipterans such as mosquitoes and tsetse flies, other arthropods such as fleas and ticks, fish such as lampreys, and mammals such as vampire bats. Wilson has characterised parasites as "predators that eat prey in units of less than one".
The senses they use to hunt with, including vision, smell, and hearing, are well developed.