The genus, Chinchilla, is a member of the family Chinchillidae, which falls into the order of Rodentia. Chinchillidae is a monophyletic group, containing the genera Chinchilla, Lagidium, and Lagostomus. These three genera are all endemic to South America. The genus, Chinchilla, is comprised of two species, Chinchilla lanigera, and Chinchilla brevicaudata (Spotorno et al. 2004a). Within the family, Chinchilla more closely related to Lagidium, the mountain viscachas, than to Lagostomus, the pampas viscachas. The distinctiveness of the two species of Chinchilla is supported by their molecular (DNA sequence) differences, morphological differences and male sterility in hybrids (Spotorno et al. 2004a). Both species of Chinchilla are now considered to be endangered in the wild (Saunders 2009). Despite coming close to extinction, they have become better known in the wild and common as domesticated pets. Chinchilla lanigera originated from north-central Chile, but is now found also in some areas in Peru, and in the low mountains and hills of Chile. Chinchilla brevicaudata came from the mountains of Peru, Argentina, Bolivia, and in the northern part of Chile. Yet, there is speculation that there are no longer any existing wild populations of C. brevicaudata (Jimènez 1996). Once discovered, these animals became valuable for their wool, meat, and pelt. Chinchillas have now become popular as domesticated pets and lab animals within the United States. There are suggestions that there has been some cross breeding between the two species in captivity (Spotorno et al. 2004a). These unique animals are small with very dense, silky fur in shades of grey, white, and black. Their long tails are generally covered in coarse black hair. In addition, they have very large ears which are important to their highly developed hearing systems. In the wild, they live in holes and tunnels, or under rocks in dry, sandy environments. As social animals, chinchillas generally live in colonies of around 100 members. These animals are mainly herbivores, feeding on various kinds of herbs and grasses (Spotorno et al. 2004b).
Distribution of Chinchilla lanigera and Chinchilla brevicaudata in South America. Adapted from (Jimènez 1996.)
Chinchillas can easily be distinguished from the other genera of Chinchillidae by their size. Whereas the viscachas (Lagidium, and Lagostomus) are large rodents of up to 9kg, the chinchillas are usually around 0.5kg. The most defining difference between Chinchilla lanigera and Chinchilla brevicaudata is in their size and body shape. Chinchilla lanigera are referred to as long-tailed chinchillas, whereas Chinchilla brevicaudata are referred to as short-tailed chinchillas (Jimènez 1996). As a whole, the most notable characteristics of the Chinchilla species are their fur and ears. The fur of these animals is known for its silky touch. The fur is very thick due to the number of hairs contained in each hair follicle. There may be up to 90 hairs emanating from each hair follicle (Saunders 2009). These hairs are adapted for keeping the animal warm in their original cold, dry climates of the mountains. The hair is also unique in that it helps to minimize dander, and is, in essence, odorless and hypoallergenic, making them desirable pets. The dorsal coat can be a variety of colors: grey white, black, charcoal, or sometimes a bluish color. The ventral coat, in comparison, is a yellow-white color. Maintenance and grooming of their hair is through dust baths, which helps to remove dirt and excess oil in the coat of the chinchilla. The “dust” in these baths should be ground pumice or silver sand (Saunders 2009).
Wild Chinchilla lanigera (long-tailed Chinchilla.) http://commons.wikimedia.org/wiki/Chinchilla
Wild Chinchilla brevicaudata (short-tailed Chinchilla.) http://commons.wikimedia.org/wiki/Chinchilla
These small rodents in the wild weigh on average 412 grams as males, and 422 grams as females. In comparison, domesticated chinchillas weigh significantly more: males at 600 grams and females at 800 grams on average (Spotorno et al. 2004b). These numbers reveal a strong sexual dimorphism between males and females. This size difference is due to structural differences between the two sexes. Female Chinchilla lanigera are characterized by larger pelvis and viscerocranium bones. Also, males tend to have a faster growth period than the females (Lammers et al. 2001). These differences in size and development between the sexes are thought to be adaptive. Females may need a larger pelvis in order to give birth to young. The viscerocranium of the female may be larger if females consume larger food items (Lammers et al. 2001). In addition to being the larger of the sexes, females also tend to be dominant over males (Saunders 2009).
Chinchillas are nocturnal animals. They tend to be most active around the hours of dawn and dusk, and sleep most of the daytime hours. They are very curious explorers of their surrounding habitats (Saunders 2009). They are capable of very quick movements such as running and jumping (Spotorno et al. 2004b). It has been recorded that they can jump to heights of five meters both horizontally as well as vertically. Chinchillas are very vocal animals, using chirps, hiccups, and clucks to communicate different feelings or emotions (Saunders 2009). When under stress they may make “eek-eek” or “nyak-nyak” noises. Shedding fur is another response to stressful conditions (Spotorno et al. 2004b).
Under captivity, these animals must be socialized and handled at a young age in order to interact positively with humans. They can make great pets for adults, but are not ideal for young children as they need to be handled with great care. Chinchillas are not generally aggressive animals; they rarely bite and never scratch (Saunders 2009).
Domestic Chinchilla http://commons.wikimedia.org/wiki/Chinchilla
Chinchillas have been documented to live to an average of six years in the wild. In zoos, this number is lessened to four years. However, in captivity, there have been chinchillas functioning as pets that live to be over 20 years old (Spotorno et al. 2004b).
Chinchilla young are born highly developed, after a short gestation period of, on average, 111 days. After birth, baby chinchillas have a full fur coat, teeth, open eyes, and weigh around 30-60 grams. Once delivered, they are able to walk within an hour. Young chinchillas reach sexual maturity within six to nine months of birth. Once they have reached sexual maturity, females may give birth to two to three litters per year. The average number of offspring per litter is generally around one to four (Saunders 2009).
The recommended amounts of dietary components for companionate chinchillas are as follows: 10-20% protein, 2-5% fat, and 15-35% bulk fiber. It is also highly suggested to supply chinchillas with timothy hay and a woodblock. Chinchilla teeth are rootless, and therefore, never stop growing. Chewing on a woodblock helps to maintain teeth and prevent oral diseases (Spotorno et al. 2004b).