Landlocked country one, making them the biggest contiguous group in the world. Also, the Central Asian and Caucasian clusters can be considered contiguous, joined by the landlocked Caspian Sea. Mongolia is almost part of this cluster too, being separated from Kazakhstan by only , across Russian or Chinese territory. There are the following "single" landlocked countries (each of them borders no other landlocked country): If the Caucasian countries and Kazakhstan are counted as part of Europe, then Europe has the most landlocked countries, at 20. If these transcontinental countries are included in Asia, then Africa has the most, at 16. Depending on
Mongolian gerbil and kill the mothers' newer pups whilst still in the family unit. The father or older brothers will mate with younger females. These young females have the ability to carry sperm for up to 2 weeks until they are sexually mature (at 3–4 months) so that they can make a family of their own without the interference of another male who may kill the fathers pups. This is why it isn't recommended to keep an older male gerbil with a younger female as a cage mate for a prolonged amount of time. Mongolian gerbil Meriones unguiculatus, the Mongolian gerbil or