Search results
Results from the WOW.Com Content Network
Cheek pouches are pockets on both sides of the head of some mammals between the jaw and the cheek. They can be found on mammals including the platypus, some rodents, and most monkeys, [1] [2] as well as the marsupial koala. [3] The cheek pouches of chipmunks can reach the size of their body when full.
The arrangement of the pouch is variable to allow the offspring to receive maximum protection. Locomotive kangaroos have a pouch opening at the front, while many others that walk or climb on all fours open in the back. Usually, only females have a pouch, but the male water opossum has a pouch that protects his genitalia while swimming or running.
Female koalas have been described as having a ‘backward-opening’ pouch like wombats, as opposed to an upward-opening pouch like kangaroos, but that is not true. When a female koala gives birth to young her pouch opening faces neither up nor down, although it is located towards the bottom of the pouch rather than at the top.
Even before the mid-19th century and Charles Darwin's time, biogeographers understood speciation and animal niches. A supreme example that became known to Darwin as sailing ships traveled the world is the New Zealand flightless, ground-dwelling, worm-eating kiwi , a bird, but a species in a mammal-niche.
Personal shielding against more energetic radiation such as gamma radiation is very difficult to achieve as the large mass of shielding material required to properly protect the entire body would make functional movement nearly impossible. For this, partial body shielding of radio-sensitive internal organs is the most viable protection strategy.
The human body contains many types of cells and a human can be killed by the loss of a single tissue in a vital organ [citation needed]. For many short term radiation deaths (3 days to 30 days) the loss of cells forming blood cells (bone marrow) and the cells in the digestive system (wall of the intestines) cause death.
The climbing ability would have also helped them climb out of caves, which could therefore have been used as dens to rear their young. [30] Specialised tail bones called chevrons strengthened the tail, likely allowing the animal to use it to prop itself up while rearing on its hind legs, which may have been done when climbing or attacking prey.
In an example of convergent evolution, the southern marsupial mole resembles the Namib Desert golden mole (Eremitalpa granti namibensis) and other specialised fossorial animals in having a low and unstable body temperature, ranging between 15–30 °C (59–86 °F). It does not have an unusually low resting metabolic rate, and the metabolic ...