Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Superorder: Xenarthra
Order: Cingulata

Armadillos (meaning "little armored ones" in Spanish) are New World placental mammals in the order Cingulata. The Chlamyphoridae and Dasypodidae are the only surviving families in the order, which is part of the superorder Xenarthra, along with the anteaters and sloths. Nine extinct genera and 21 extant species of armadillo have been described, some of which are distinguished by the number of bands on their armor. All species are native to the Americas, where they inhabit a variety of different environments.

Armadillos are characterized by a leathery armor shell and long sharp claws for digging. They have short legs, but can move quite quickly. The average length of an armadillo is about 75 cm (30 in), including tail. The giant armadillo grows up to 150 cm (59 in) and weighs up to 54 kg (119 lb), while the pink fairy armadillo has a length of only 13–15 cm (5–6 in). When threatened by a predator, Tolypeutes species frequently roll up into a ball (these being the only species of Armadillo capable of such).

Characteristics
Size
Armadillos are small to medium-sized mammals. The smallest species, the pink fairy armadillo, is roughly chipmunk-sized at 85 g (3.0 oz) and 13–15 cm (5.1–5.9 in) in total length. The largest species, the giant armadillo, can reach the size of a small pig and weigh up to 54 kg (119 lb), and can be 150 cm (59 in) long.

Diet and predation
They are prolific diggers. Many species use their sharp claws to dig for food, such as grubs, and to dig dens. The nine-banded armadillo prefers to build burrows in moist soil near the creeks, streams, and arroyos around which it lives and feeds. The diets of different armadillo species vary, but consist mainly of insects, grubs, and other invertebrates. Some species, however, feed almost entirely on ants and termites.

Armadillos have very poor eyesight, and use their keen sense of smell to hunt for food. They use their claws for digging and finding food, as well as for making their homes in burrows. They dig their burrows with their claws, making only a single corridor the width of the animal's body. They have five clawed toes on their hind feet, and three to five toes with heavy digging claws on their fore feet. Armadillos have numerous cheek teeth which are not divided into premolars and molars, but usually have no incisors or canines. The dentition of the nine-banded armadillo is P 7/7, M 1/1 = 32.

Body temperature
In common with other xenarthrans, armadillos, in general, have low body temperatures of 33–36 °C (91–97 °F) and low basal metabolic rates (40–60% of that expected in placental mammals of their mass). This is particularly true of types that specialize in using termites as their primary food source (for example, Priodontes and Tolypeutes).

Skin
The armor is formed by plates of dermal bone covered in relatively small, overlapping epidermal scales called "scutes", composed of bone with a covering of horn. Most species have rigid shields over the shoulders and hips, with a number of bands separated by flexible skin covering the back and flanks. Additional armor covers the top of the head, the upper parts of the limbs, and the tail. The underside of the animal is never armored, and is simply covered with soft skin and fur.

This armor-like skin appears to be the main defense of many armadillos, although most escape predators by fleeing (often into thorny patches, from which their armor protects them) or digging to safety. Only the South American three-banded armadillos (Tolypeutes) rely heavily on their armor for protection.

Defensive behavior
When threatened by a predator, Tolypeutes species frequently roll up into a ball. Other armadillo species cannot roll up because they have too many plates. The North American nine-banded armadillo tends to jump straight in the air when surprised, so consequently often collides with the undercarriage or fenders of passing vehicles to its demise.

Movement
Armadillos have short legs, but can move quite quickly. The nine-banded armadillo is noted for its movement through water which is accomplished via two different methods: it can walk underwater for short distances, holding its breath for as long as six minutes; also, to cross larger bodies of water, it is capable of increasing its buoyancy by swallowing air, inflating its stomach and intestines.

Reproduction
Gestation lasts from 60 to 120 days, depending on species, although the nine-banded armadillo also exhibits delayed implantation, so the young are not typically born for eight months after mating. Most members of the genus Dasypus give birth to four monozygotic young (that is, identical quadruplets), but other species may have typical litter sizes that range from one to eight. The young are born with soft, leathery skin which hardens within a few weeks. They reach sexual maturity in three to twelve months, depending on the species. Armadillos are solitary animals that do not share their burrows with other adults.

Kingdom: Animalia
Phylum: Echinodermata
Class: Holothuroidea
Order: Apodida
Family: Synaptidae
Genus: Synapta
Species: S. maculata

Synapta maculata , the snake sea cucumber, is a species of sea cucumber in the family Synaptidae. It is found in shallow waters in the tropical Indo-Pacific Ocean. Sometimes growing as long as 3 m (10 ft), it is one of the longest sea cucumbers in the world.

Description
S. maculata is a long, slender sea cucumber with fifteen tentacles, growing to a length of about 2 m (7 ft). Although not the heaviest or bulkiest sea cucumber in the world, it is probably the longest, with individuals exceptionally reaching to over 3 m (10 ft). Its colouring is variable, being some shade of yellowish-brown with wide longitudinal stripes and patches of darker colour. The spicules (microscopic calcareous spike-like structures that support the body wall) are large and shaped like anchors and are used in locomotion; they can be as long as 2 mm. The spicules are adhesive, and the sea cucumber is very difficult to detach from a wetsuit.

Distribution and habitat
The species is native to the tropical western Indo-Pacific region. It occurs at depths down to about 20 m (66 ft) on reefs and on soft sediments on the seabed among seagrasses and seaweeds. It can also bury itself under rubble.

Biology
The tentacles of Synapta maculata surround the mouth and are used in surface feeding. They are about 2.5 cm (1 in) long when extended and have a short stem and a feather-like blade with thirty to forty pairs of pinnules. The outer surfaces of the tentacles have numerous bulges and are adhesive while the inner surfaces are smooth, with clusters of cilia on the proximal parts. The tentacles are in continuous motion; they flatten themselves against the substrate or seagrass leaf blades and collect food particles by adhesion, then bend inwards until the tips are in the mouth, where the food is scraped off by the buccal sphincter muscle. The whole process takes only a few seconds, and several tentacles can deliver their loads at the same time. If the animal is disturbed, the tentacles can contract back into the pharynx, but before long they are out again, collecting more particles.

The outer surface of the tentacles bears numerous vesicular cells, and there are a few scattered vesicles on the body surface also. The function of these cells is unclear, but it is suggested that they may contain a noxious substance and serve a defensive function. The tentacles are particularly vulnerable to predation by fish, but if they taste nasty, that enables the sea cucumber to spend a greater proportion of its time feeding, rather than having to keep retracting its tentacles whenever a fish approaches. There are also some cup-shaped structures on the inside of the tentacles near the stem. It is hypothesized that these are rudimentary sensory organs, able to taste the edibility of the food material that the animal is transporting to its mouth.

A defensive response made by many sea cucumbers is evisceration, but in the case of S. maculata, autotomy is preferred, with large individuals dispensing with sections near the rear end while smaller individuals break into many pieces. Two previously unknown triterpene holostane glycosides have been isolated from S. maculata; one has moderate activity against HeLa tumour cells while the other is inactive.

In literature
Naturalist Gerald Durrell's 1977 observations of this creature were made when he was snorkeling in shallow water in Mauritius:

"At first, I could not believe that these weird objects were alive. I thought they must be strange, dead strands of some deep-sea seaweed now washed into the shallows by the tide, to roll and undulate helplessly on the sand to the small movements of the sea. Closer inspection showed me that they were indeed alive, unlikely though it seemed. Sinucta muculata [sic], as this strange creature is called, is really a sort of elongated tube, which sucks in water at one end and with it microscopic organisms, and expels the water at the other."