Figure 2. Sexual dimorphism in the growth rate of zebra finch embryos arises after 36 h of incubation.

A – Hamburger & Hamilton stage, B – number of somites in male and female embryos in relation to incubation time. Sample sizes for female estimates are 30, 4 and 5 and for male estimates 32, 4 and 6 embryos for incubation of 36, 37 and 40 hours respectively. Mean ± SE are presented.