While Homo sapiens usually have 46 chromosomes there are individuals
with 45 chromosomes (Turner's syndrome), 47 chromosomes (Down,
Klinefelter's, XYY and XXY syndromes) and even 48 chromosomes (XXYY
syndrome). Most of these variants are fertile and able - with
individuals with the "normal" complement of 46 chromosomes - to produce
children.

Are there other species also with a variant chromosome count? Or do we
know? Homo sapiens is, no doubt, the species we know most about and
maybe such variation has eluded detection in other species?