Comparing Cats: A Discussion of Similarities & Differences

[Acinonyx sp.]

Smilodon fatalis siblings reveal life history in a saber-toothed cat

Summary

The saber-toothed cat Smilodon fatalis is known predominantly from “predator trap” deposits, which has made many aspects of its life history difficult to infer. Here, we describe an association of at least two subadult and one adult S. fatalis from Pleistocene coastal deposits in Ecuador. The assemblage likely derived from a catastrophic mass mortality event, and thereby provides insights into the behavior of the species. The presence of a P3 in the subadult dentaries suggests inheritance, a rare instance of familial relatedness in the fossil record. The siblings were at least two years old and were associated with an adult that was likely their mother, indicating prolonged parental care in S. fatalis. Comparison with the growth of pantherine cats suggests that S. fatalis had a unique growth strategy among big cats that combines a growth rate that is similar to a tiger and the extended growth period of a lion.



'For example, high levels of sociality in S. fatalis have been considered plausible by some authors (Akersten (1985); Carbone et al. (2009); Christiansen and Harris (2012); Friscia et al. (2008); Gonyea (1976); Meachen-Samuels and Binder (2010); Van Valkenburgh and Sacco (2002)), but unlikely by others (Kiffner (2009); McCall et al. (2003)). Furthermore, it has been argued that S. fatalis would not have lived in polygynous groupings because of its putative reduced sexual dimorphism, but the possibility of social groups where polygamy or monogamy are the primary mating system cannot be discounted (Christiansen and Harris (2012); Meachen-Samuels and Binder (2010); Van Valkenburgh and Sacco (2002)).'


'At two years old, tigers (Panthera tigris) have been independent from their mothers for at least six months and weigh between 68% (males) and 94% (females) of their asymptotic body mass (Jones et al. (2009); Slaght et al., 2005). Meanwhile, two-year-old lions are nearly a year from independence and weigh from 58% (males) to 72% (females) of asymptotic body mass (Jones et al. (2009); Smuts et al. (1980)).'

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