Phodopus, a genus of rodents in the hamster subfamily Cricetinae—a division of the larger family Cricetidae—is a lineage of small hamsters native to central Asia that display unusual adaptations to extreme temperatures. They are the only known hamsters that live in groups and, as shown in Phodopus campbelli, rely on significant contributions by males to the raising of offspring. They are nocturnal and active throughout the year; they do not hibernate. Species of Phodopus, together with members of the genera Cricetulus, Allocricetulus and Tscherskia are called dwarf hamsters because of their small size (roughly ) relative to other hamsters.
All three species are widespread and probably abundant, and are assessed as Least Concern (LC) by the IUCN Red List, However, their ecology and population dynamics are not well understood. Historical records indicate they were once common in places where they no longer occur. It contains hamsters distinguished from other hamsters by small size, short tails and fur covered feet. despite the fact that molecular data suggest the lineage is no younger than 8.5 million years.
Gerrit Smith Miller Jr. first described the genus Phodopus in 1910, designating Cricetulus bedfordiae as its type species. The genus Phodopus is one of three well-supported lineages in Cricetinae, the other two being the genus Mesocricetus and the Cricetus-related group (Cricetus, Tscherskia, Allocricetulus, and Cricetulus). Analysis of chromosomes supports these three lineages. Phodopus is sister to all other Cricetinae (meaning that it is the first lineage to diverge in the clade). Using several molecular dating techniques, researchers have determined that the Phodopus lineage may have originated 8.5 to 12.2 million years ago (mya). Other genetic dating analyses suggest a somewhat earlier origination of 13.5–14.1 mya. Fossils assignable to the genus are unknown before about 2.5 million years ago, but failure to identify the remains accurately may contribute to the apparent lack of older fossils.
As shown in the cladogram, Phodopus roborovskii is sister to Phodopus campbelli + Phodopus sungorus. The validity of P. campbelli as a species has been controversial. Some biologists consider it to be a subspecies of P. sungorus. Neumann et al.
P. roborovskii, on the other hand, has levels of genetic divergence from the other two taxa in the genus characteristic of genera among small mammals. P. roborovskii is also distinct from the other species morphologically (in its smaller body size and pelage, for example) and ecologically (preferring sandy, arid habitats). P. roborovskii has 2n=34 chromosomes. For these reasons, Neumann et al. P. sungorus and P. roborovskii. The validity of P. campbelli is in dispute, and it has sometimes been considered a subspecies of P. sungorus.
The species of Phodopus do not have stable common names, even among biologists. "Djungarian" (or "Dzhungarian" or "Zungarian") and "Siberian" have been applied to both P. sungorus and P. campbelli in the scientific literature, and all three species have been called "desert" hamsters as well.
P. sungorus is known as:
:Djungarian [or Dzhungarian The fur on the abdomen is grey, and the coat colour turns grey during moulting.
Adaptations to extreme environments
Phodopus species display a variety of morphological, physiological and behavioral adaptations to seasonal temperature extremes and aridity. To survive the exceptional cold of winter, they have evolved spherical, compact bodies with excellent insulation, including both fur and fat. Water is scarce in both summer and winter, and these hamsters have developed an excellent ability to conserve water by maintaining low evaporative water loss rates and concentrating urine. They also eat other plant parts and insects.
Habitats and conservation status
Phodopus species inhabit the mountainous forests, steppes, and semideserts of Mongolia and the adjacent areas of China, northeast Kazakhstan, and the southern part of the West Siberian lowlands of Tuva and Dauria. All three species are widespread, although some isolated local populations exist. All three species are probably abundant and are assessed as Least Concern (LC) in the IUCN Red List. They all occur to some extent in protected areas, at least in Mongolia, and are not thought to face significant threats to their existence. Because the status and dynamics of their populations are uncertain, some species are treated as species of concern (for example, the government of Kazakhstan requires monitoring of P. roborovskii)
Some species are clearly diminished in range and may have been extirpated as agricultural pests or by habitat destruction.
Interactions with humans
Since some populations and species of Phodopus, such as P. campbelli, inhabit areas with sparse human population and little potential for agriculture, they have little interaction with humans.. They are considered excellent pets, especially for novice pet owners, because they are easy to maintain (requiring no special diet or conditions), are generally not aggressive to people, and tolerate living with other members of their species.
Phodopus species have developed into important laboratory organisms. They provide an excellent model system for the evolution of hormonal control of photoperiod and seasonal physiological and behavioral changes, sociality, and behavioral ecology. Because Phodopus species have small chromosome numbers with easily distinguished chromosomes, they have been used for cytogenetic and cancer research.