The karyotype of the red brocket was initially described as having 2n = 68, FN = 74, and more recently as having 2n varying from 48 to 54 and FN varying from 54 to 56.
Кариотип большой мазамы был первоначально описан как имеющий 2n = 68, FN = 74, а в последнее время с 2n, варьирующимся от 48 до 54 и FN — от 54 до 56.