Animals are multicellular, eukaryotic organisms of the kingdom Animalia (also called Metazoa). Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their lives. Most animals are motile, meaning they can move spontaneously and independently. Most all animals must ingest other organisms or their products for sustenance, with the exception of those that form symbiotic relationships with photosynthetic organisms.
Most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago. Animals are divided into various sub-groups, some of which are: vertebrates (birds, mammals, amphibians, reptiles, fish); mollusks (clams, oysters, octopuses, squid, snails); arthropods (millipedes, centipedes, insects, spiders, scorpions, crabs, lobsters, shrimp); annelids (earthworms, leeches); sponges; and jellyfish.
Entoprocta is a phylum of mostly sessile aquatic animals, ranging from 0.1 to 7 millimetres (0.0039 to 0.28 in) long. Mature individuals are goblet-shaped, on relatively long stalks. They have a "crown" of solid tentacles whose cilia generate water currents that draw food particles towards the mouth, and both the mouth and anus lie inside the "crown". The superficially similar Bryozoa (Ectoprocta) have the anus outside a "crown" of hollow tentacles. Most families of entoprocts are colonial, and all but 2 of the 150 species are marine. A few solitary species can move slowly. Some species eject unfertilized ova into the water while others keep their ova in brood chambers until they hatch, and some of these species use placenta-like organs to nourish the developing eggs. After hatching, the larvae swim for a short time and then settle on a surface. There they metamorphose, and the larval gut generally rotates by up to 180°, so that the mouth and anus face upwards. Both colonial and solitary species also reproduce by cloning – solitary species grow clones in the space between the tentacles and then release them when developed, while colonial ones produce new members from the stalks or from corridor-like stolons. Some species of nudibranchs ("sea slugs") and turbellarian flatworms prey on entoprocts. A few entoproct species have been found living in close association with other animals. It is uncertain whether any are invasive species.
The white-necked petrel (Pterodroma cervicalis) is a seabird in the family Procellariidae; adults measure some 43 centimetres (17 in) in length, with a wingspan of 95–105 centimetres (37–41 in). Although the species is found in much of the South Pacific, it breeds on only three islands and is thus considered vulnerable by the IUCN.
When the fox dies, fowls do not mourn.
The Javan rhinoceros
is a member of the family Rhinocerotidae
and one of five extant rhinoceroses
. Its horn is usually less than 25 cm (10 inches), smaller than those of the other rhino species. Once the most widespread of Asian rhinoceroses, the Javan rhinoceros ranged from the islands of Java
, throughout Southeast Asia, and into India and China. The species is critically endangered
, with only one known population in the wild, and no individuals in captivity. It is possibly the rarest large mammal on earth, with a population of as few as 40 in Ujung Kulon National Park
. The decline of the Javan rhinoceros is attributed to poaching, primarily for their horns, which are highly valued in traditional Chinese medicine
. The Javan rhino can live approximately 30–45 years in the wild. It historically inhabited lowland rain forest
, wet grasslands and large floodplains. The Javan rhino is mostly solitary, except for courtship and offspring-rearing, though groups may occasionally congregate near wallows and salt licks. Aside from humans, adults have no predators
in their range. Scientists and conservationists rarely study the animals directly due to their extreme rarity and the danger of interfering with such an endangered species. Researchers rely on camera traps
and fecal samples to gauge health and behavior. Consequently, the Javan rhino is the least studied of all rhino species.