Modem analogs for dinosaur nesting and parental behavior

Respiratory and Reproductive Paleophysiology of Dinosaurs and Early Birds

“…Birds and oviparous reptiles display a wide range of incubation behaviors. However, although many may closely guard their nests (Cott 1961(Cott , 1971Martoff et al 1980;Shine 1988;Coombs 1989;Lang 1989;Gans 1996;Geist and Jones 1996;Pough et al 1998), extant reptiles are not known to directly manipulate their nests or eggs to control the temperature. Living birds almost universally incubate their eggs by brooding (Welty and Baptista 1988;Gill 1994).…”

“…However, close proximity and even physical contact of parent and nests occur widely among reptiles, including turtles, squamates, and crocodilians (Gans 1996;Shine 1988;Pough et al 1998). Female crocodilians often lie on top of the nest during nest guarding (Coombs 1989;Lang 1989), and it has been reported that they will rest their lower throat or thorax directly on the nest during the incubation period (Cott 1961(Cott , 1971. Consequently, the position of the oviraptorid on the nest does not necessarily signal avian-style brooding.…”

Phylogenetic reconstruction of parental–care systems in the ancestors of birds

“…Although there are problems with inferring behaviour from fossils, some dinosaur fossils are regarded as strong evidence of parental care. Findings of nests with eggs and young in various associations with adults are widely regarded as evidence of parental care in several dinosaur lineages (Coombs 1982(Coombs , 1989Horner 1984;Norell et al 1995;Varricchio et al 1997). These findings have been regarded as an indication that parental attendance of eggs may be primitive for dinosaurs, that brooding behaviour evolved before the avian clade (Norell et al 1995) and that postoviposition care is homologous for Archosauria (Coombs 1989;Varricchio et Phil.…”

“…If brooding and an extended egg-laying period indicate a long pair bond between mates as suggested by Varricchio et al (1997), biparental care might indeed have preceded the split between birds and other dinosaurs. Coombs (1989) finds it likely with male assisting the female in guarding nests and providing care to young, but regards the caring sex(es) as an open question because all types of care systems are present in extant archosaurs.…”

“…The outgroups to birds vary in their parental care patterns. For instance, crocodilians are known to have both biparental and uniparental female care (Shine 1988;Coombs 1989), and it is therefore important to include various crocodilian taxa in a phylogenetic analysis. Moreover, phylogenetic reconstruction is more reliable when several outgroups (Maddison et al 1984) and, if possible, fossils (Donoghue et al 1989) are included.…”