Reproductive suppression is common among mammals residing in cooperative social systems and is characterized by the cessation of ovulation in subordinate females until their social environment releases them from a temporary freeze on ovulating (e.g., dwarf mongoose, Helogale parvula (Creel, Creel, Wildt, & Monfort, 1992); African wild dogs, Lycaon pictus (Creel, Creel, Mills, & Monfort, 1997); wolves, Canus lupus (Packard, Seal, Mech, & Plotka, 1985); Damaraland mole rats, Cryptomys damarensis (Bennett, 1994); common marmosets, Callthrix jacchus (Barrett, Abbott, & George, 1993); cotton-top tamarins, Saguinus oedipus (Ziegler, Savage, Scheffler, & Snowdon, 1987)). The prevalent evolutionary explanation for the inhibition of ovulation is that female–female competition regulates ovarian cyclicity (Wasser & Barash, 1983). Reproductive cessation is a problem among mammals residing in zoological institutions, where, despite abundant veterinary care and an adequate diet, some females fail to breed (Morfeld & Brown, 2014; Penfold, Powell, Taylor-Holzer, & Asa, 2014; Saunders, Harris, Taylor-Holzer, & Beck, 2014). Reproductive abnormalities occur among animals exposed to organic pollutants (Murphy et al., 2015) and endocrine disrupters (Norris & Carr, 2005; Tubbs & McDonough, 2018) that hinder the ability to produce viable young.
