Common names: Aruba rattlesnake, Aruba island rattlesnake.

Crotalus durissus unicolor is a venomous

Venomous snake

"Poisonous snake" redirects here. For true poisonous snakes, see Rhabdophis.Venomous snakes are snakes which have venom glands and specialized teeth for the injection of venom...

 pitviper

Crotalinae

The Crotalinae, commonly known as "pit vipers" or crotaline snakes, are a subfamily of venomous vipers found in Asia and the Americas. They are distinguished by the presence of a heat-sensing pit organ located between the eye and the nostril on either side of the head...

 subspecies

Subspecies

Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

 found only on the Caribbean

Caribbean

The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...

 island of Aruba

Aruba

Aruba is a 33 km-long island of the Lesser Antilles in the southern Caribbean Sea, located 27 km north of the coast of Venezuela and 130 km east of Guajira Peninsula...

, off the coast of Venezuela

Venezuela

Venezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...

. Critically endangered, it is estimated that fewer than 230 adults survive in the wild. Sometimes still treated as a full species.

Description

Moderately sized, this species attains an adult length of approximately 90 cm. It is light brown

Brown

Brown is a color term, denoting a range of composite colors produced by a mixture of orange, red, rose, or yellow with black or gray. The term is from Old English brún, in origin for any dusky or dark shade of color....

, tan

Tan (color)

Tan is a pale whiteish, tawny shade of white. The name is derived from tannum used in the tanning of leather.The first recorded use of tan as a shade name in English was in the year 1590....

, or almost pink

Pink

Pink is a mixture of red and white. Commonly used for Valentine's Day and Easter, pink is sometimes referred to as "the color of love." The use of the word for the color known today as pink was first recorded in the late 17th century....

 in color, reflecting the soil color of its native habitat, with darker brown diamond shaped markings but colors may vary from white to apricot, or brown to slate. The markings are sometimes nearly invisible, or only visible in a narrow stripe down the middle of the back.

Geographic range

Endemic to the island of Aruba

Aruba

Aruba is a 33 km-long island of the Lesser Antilles in the southern Caribbean Sea, located 27 km north of the coast of Venezuela and 130 km east of Guajira Peninsula...

, off the coast of Venezuela

Venezuela

Venezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...

. They exist only in thornscrub and desert habitats on the southeastern half of the island. The type locality given is "Aruba."

Conservation status

This species is classified as critically endangered (CR) on the IUCN Red List for the following criteria: C2b (v2.3, 1994). This means that the population is estimated to number less than 250 mature individuals, a continuing decline has been observed, projected, or inferred, in the number of mature individuals, and that the population structure is such that all individuals are in a single subpopulation. Year assessed: 1996.
These snakes are found only on the island of Aruba, where they are mostly limited to the rocky, dry southern tip of the island. Due to their extremely limited geographic range, about 230 animals left in the wild, and the ever encroaching human habitation into their territory (there is only about 25 square kilometers left undeveloped), the Aruba Island rattlesnake is among the rarest rattlesnakes in the world and listed as critically endangered

Endangered species

An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...

. Unfortunately, while exporting from the island is illegal, it has no other legal protection on the island either. The snake is now a part of the Species Survival Plan

Species Survival Plan

The American Species Survival Plan or SSP program was developed in 1981 by the Association of Zoos and Aquariums to help ensure the survival of selected species in zoos and aquariums, most of which are threatened or endangered in the wild....

 for captive breeding

Captive breeding

Captive breedingis the process of breeding animals in human controlled environments with restricted settings, such as wildlife reserves, zoos and other conservation facilities; sometimes the process is construed to include release of individual organisms to the wild, when there is sufficient...

.

Reproduction

Males reach sexual maturity in four years; females in five. After a gestation time of four months, females give birth to between five and fifteen live young at a time.