Papo MarmosetPapo Marmoset Papo Model 50313 Product Dimensions: 6. 5 x 2. 2 x 3. 4 cm Age: 3 years and up Marmosets tend to stay in the treetops and behave a lot like squirrels. They have long tails that are longer than their bodies, but unlike other New World monkeys (capuchins and squirrel monkeys, for example), their tails are not prehensile. That means marmosets can not use their tails to grasp things. However, their tails do help them keep their balance as