Generally, two different species of chameleon have to be in the same genus in order for mating to happen. Even if they are different species in the same genus, they might not even attempt to mate. In the off chance that they do, their eggs are likely to be infertile and offspring might not be viable. That being said, Senegals are of the Chamaeleo genus, whereas Jackson's are of the Trioceros genus, meaning an attempt to mate them will most likely not work out.