The rarest animals

Rarely, less often, least often ...

Many animal species that were widespread in their natural habitat just a few years or decades ago are now threatened with extinction and are therefore considered by researchers to be one of the rarest animals in the world. However, other species are so scarce because their habitat is confined to a single distribution area and they are extremely rare for scientists to detect as they live in hard-to-reach habitats.
These include, for example, Allonautilus scrobiculatus, a cephalopod order numbered for marine life, which marine biologists have only seen three times since its discovery by US biology professor Peter Ward in 1984. Therefore, it is today named by many researchers as the rarest species in the world. This animal, called a living fossil, lives in the depths of the seas around Papua New Guinea and is said to have already colonized the earth before the dinosaurs. Allonautilus scrobiatus survived two ice ages, though this cephalopod, with its eye-catching red and white striped housing, is said to be extremely demanding in terms of its environment and habitat. It is only found at depths of several hundred meters, and it is extremely sensitive to high water temperatures and high temperature fluctuations.
Some of the rarest species are found in much more accessible locations, but their habitat is limited to a single island or forest area, so their survival is very high today. These include, for example, the Grenadataube or Leptotila wellsi, which inhabits only a few forests on the Atlantic island of Grenada. Since these have been converted into residential areas for several decades, the Grenadataube is one of the rarest species of animals today. The possums, cats and rats brought in by the settlers in the past have also contributed to the extinction of Leptotila wellsi.
Also, the name of the rare Cuban crocodile or Corocodylus rhombifer indicates that the range of this species is limited to a single region. This extremely aggressive and more than three and a half meters long representative of crocodiles occurs today only in a single wetland on the Zapata Peninsula and in the waters of the Cuban side island of Isla de la Juventud.
Among those species that are becoming increasingly rare due to human-induced changes in their environment or intensive hunting, the Sumatran orangutan is considered the most significant exponent. He has already died out in many parts of his native Sumatra, as the forests in which he lives continue to decline due to deforestation. Today, researchers estimate the stocks to be only about five thousand and assume that the Sumatran orangutan will be extinct in the next few years if no specific measures are taken to preserve its species.
Other less well-known animal species are so rare today that only a few hundred of them inhabit the earth. These include, for example, the Hunters lyre antelope or Damaliscus hunteri, the rarest antelope in the world. In recent decades, the stocks have been reduced from several thousand copies to three hundred animals. The Malagasy Schnabelschildkröte is now so rare that its stock is estimated at only about four hundred copies. Even rarer is the light-headed tail langur or Trachypithecus poliocephalus, a small primate among the lean-headed monkeys. All fifty surviving specimens inhabit the forest areas of Cát Bà, an island off Vietnam. Equally rare is Rana vibicaria, a frog native to many South American forests that can only be found in three tiny areas of the rainforests of Costa Rica today. Researchers have tried in vain to find this frog species in Panama, where it was widespread a few decades ago.