Temporal niche expansion in mammals from a nocturnal ancestor after dinosaur extinction

Abstract

Most modern mammals, including strictly diurnal species, exhibit sensory adaptations to nocturnal activity that are thought to be the result of a prolonged nocturnal phase or 'bottleneck' during early mammalian evolution. Nocturnality may have allowed mammals to avoid antagonistic interactions with diurnal dinosaurs during the Mesozoic. However, understanding the evolution of mammalian activity patterns is hindered by scant and ambiguous fossil evidence. While ancestral reconstructions of behavioural traits from extant species have the potential to elucidate these patterns, existing studies have been limited in taxonomic scope. Here, we use an extensive behavioural dataset for 2,415 species from all extant orders to reconstruct ancestral activity patterns across Mammalia. We find strong support for the nocturnal origin of mammals and the Cenozoic appearance of diurnality, although cathemerality (mixed diel periodicity) may have appeared in the late Cretaceous. Simian primates are among the earliest mammals to exhibit strict diurnal activity, some 52-33 million years ago. Our study is consistent with the hypothesis that temporal partitioning between early mammals and dinosaurs during the Mesozoic led to a mammalian nocturnal bottleneck, but also demonstrates the need for improved phylogenetic estimates for Mammalia.

Time and ecological resilience: can diurnal animals compensate for climate change by shifting to nocturnal activity?

“…, Maor et al. ), suggesting that diurnal species could develop evolutionary adaptations to cope with the novel conditions of the night. However, given the rapidness of current climate change, the rate of climate warming may be too fast for diurnal species to gradually develop nocturnal adaptations.…”

“…Diurnal mammals are an excellent model system to study the ability of animals to switch activity patterns. Evolutionary theory suggests that most early eutherian mammals were nocturnal (Wiens et al 1986, Maor et al 2017, avoiding predation and competition by the big diurnal reptiles, the dinosaurs (Clarke and P€ ortner 2010, but see Schmitz and Motani 2011). Many nocturnal adaptations evolved in mammals during the Mesozoic Era, until the extinction of the dinosaurs allowed the radiation of mammals into daytime niches (Gerkema et al 2013).…”

“…For diurnal individuals, night-time activity may entail at least one obvious cost: they will be outperformed by nocturnal animals that possess sensory adaptations in vision, hearing, and smell for sensing an environment under low light conditions (e.g., Bolen and Green 1997, Warrant 1999, Takahashi 2010, as well as other nocturnal adaptations. Nevertheless, in spite of the evolutionary constraints, species have shifted activity patterns in the past (Roll et al 2006, Maor et al 2017), suggesting that diurnal species could develop evolutionary adaptations to cope with the novel conditions of the night. However, given the rapidness of current climate change, the rate of climate warming may be too fast for diurnal species to gradually develop nocturnal adaptations.…”

“…, Maor et al. ), avoiding predation and competition by the big diurnal reptiles, the dinosaurs (Clarke and Pörtner , but see Schmitz and Motani ). Many nocturnal adaptations evolved in mammals during the Mesozoic Era, until the extinction of the dinosaurs allowed the radiation of mammals into daytime niches (Gerkema et al.…”

Behavioural plasticity modulates temperature‐related constraints on foraging time for a montane mammal

“…Nocturnal activity has also been recorded in collared pikas (O. collaris); however, much of this activity was in association with extended day length at the high-latitude study site (Morrison et al, 2009). While much remains to be learned about the role of nocturnal food-collection in pikas, nighttime activity may be constrained by increased predation risk (Maor, Dayan, Ferguson-Gow, & Jones, 2017) and/or other factors (Gaynor, Hojnowski, Carter, & Brashares, 2018). While much remains to be learned about the role of nocturnal food-collection in pikas, nighttime activity may be constrained by increased predation risk (Maor, Dayan, Ferguson-Gow, & Jones, 2017) and/or other factors (Gaynor, Hojnowski, Carter, & Brashares, 2018).…”