Galea spixii and G. musteloides are similar and may actually be the same species. G. spixii tolerates a wide range of environmental changes, though they need open habitats. It is the most stable species within the Galea group because it is extremely abundant throughout its range.[3]
Gestation is about fifty days. Litter size ranges from one to five, with an average of three. They have hair and open eyes at birth.[4] Maturation of the two sexes takes differently long: female G. spixii have an open vagina when they are approximately eighty days old while the testicular descent is completed in male G. spixii at around one hundred thirty-five days old. Males and females in this species are aggressive to each other. Paternal care is rarely remarkable. When females go into estrus aggressiveness increases. On the other hand, when male approaches females in order to mate, it competes aggressively with other males.[5] A study done in Brazil reported that nine male cavies were put to death to experiment their sperm recovery by soaking or injecting their sperm into a liquid that contained a chemical buffer. Unfortunately, there were no distinctive results between either soaking or injecting.[6]
^Catzeflis, F., Patton J., Percequillo, A., Bonvicino, C. & Weksler, M. 2008. Galea spixii. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.1. www.iucnredlist.org. Downloaded on 08 October 2013.
^ADRIAN, O., & SACHSER, N. (2011). Diversity of social and mating systems in cavies: a review.Journal of Mammalogy, 92(1), 39-53. doi:10.1644/09-MAMM-S-405.1
^da Silva et al.(2016) Characterization of epididymal sperm from Spix's yellow‐toothed cavies (Galea spixii Wagler, 1831) recovered by different methods.Acta Zoologica (Stockholm) 98: 285– 291.