Jack McCormack: MRes Student 2021-2022
MRes student at Swansea University. Co-supervised by Dr Hazel Nichols and Dr Kevin Arbuckle.
Project title: The potential fitness benefits of grandmothers in long finned pilot whale societies.
Long-finned pilot whales (Globicephala melas) are a species of toothed whale (Odontoceti) which live in groups of anywhere between 10 to 1000 individuals. Much like their sister species, the short-finned pilot whale (Globicephala macrorhynchus), and other closely related species such as killer whales (Orcinus orca), offspring display bisexual philopatry, meaning that both sexes remain in their maternal pod for life. It has been suggested that 4 species of toothed whale, killer whales, short-finned pilot whales, beluga whales (Delphinapterus leucas) and narwhals (Monodon monoceros) undergo permanent reproductive senescence (menopause) in order to aid their daughters in raising philopatric offspring, known as the ‘grandmother effect’, and to avoid direct reproductive competition with daughters. Unlike these closely related species, however, long-finned pilot whales have not evolved a post-reproductive lifespan. In this study I aim to assess whether long-finned pilot whale grandmothers provide fitness benefits to their grand-offspring despite being reproductively active, and to what extent this occurs. This study should reveal more about the selective pressures and evolutionary conditions necessary for the evolution of menopause.
Project title: The potential fitness benefits of grandmothers in long finned pilot whale societies.
Long-finned pilot whales (Globicephala melas) are a species of toothed whale (Odontoceti) which live in groups of anywhere between 10 to 1000 individuals. Much like their sister species, the short-finned pilot whale (Globicephala macrorhynchus), and other closely related species such as killer whales (Orcinus orca), offspring display bisexual philopatry, meaning that both sexes remain in their maternal pod for life. It has been suggested that 4 species of toothed whale, killer whales, short-finned pilot whales, beluga whales (Delphinapterus leucas) and narwhals (Monodon monoceros) undergo permanent reproductive senescence (menopause) in order to aid their daughters in raising philopatric offspring, known as the ‘grandmother effect’, and to avoid direct reproductive competition with daughters. Unlike these closely related species, however, long-finned pilot whales have not evolved a post-reproductive lifespan. In this study I aim to assess whether long-finned pilot whale grandmothers provide fitness benefits to their grand-offspring despite being reproductively active, and to what extent this occurs. This study should reveal more about the selective pressures and evolutionary conditions necessary for the evolution of menopause.