Depends which animals! For the simple case of a male and a female from the same species, then sure. For different species, then it depends how different they are – some cross-species breeding is possible (like the lion-tiger hybrid called a liger that Sarah mentioned), but if the species are more than a tiny bit different from each other than interbreeding becomes impossible.
The catch, though, is that interbreeding between two similar-but-different species often leads the offspring to have strange genetic defects like infertility and other health problems.
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