Why are most hybrid animals inferile?

Question

*i meant infertile

Answer 1

Hybrids formed from two different species will have inherited different chromosomes and hence different genes.

In order to produce gametes for sexual reproduction homologous pais of chromosomes align in Meiosis I.

Since they cannot form homologous pairs as the chromosomes carry different genes, they cannot undergo Meiosis to form gametes and are infertile.

Hope this helps!

Answer 2

It is often true.  I know of sources that say that there really isn't a large correlation in infertility in hybrids. Mules are such a famous example that it is often assumed that all hybrids are.  In their case, the different number and composition of chromosomes means that their sperm or eggs will not likely get complete sets of all genes so their egg or sperm may be missing one of the vital genes.  Any offspring fertilized from that sperm will likely be missing something.  The same goes for the eggs.