The study investigates the evolution of menopause in toothed whales, a unique opportunity to understand the adaptive value of menopause in a comparative context. Toothed whales are the only mammal taxon where menopause has evolved multiple times, providing a rich dataset for analysis. The researchers used Bayesian mortality models and ovarian corpora data to estimate lifespan and reproductive lifespan for 32 species of toothed whales. They found that menopause evolved in these whales by extending their total lifespan without increasing their reproductive lifespan, supporting the 'live-long' hypothesis. Additionally, they showed that menopause allows females to increase their lifespan overlap with their grandoffspring and offspring without increasing their reproductive overlap with their daughters, enhancing intergenerational help. These findings are consistent with the evolutionary theories of ageing and suggest that the same pathways that led to menopause in humans can also explain its evolution in toothed whales. The study also highlights the importance of intergenerational help and the balance between reproductive and non-reproductive benefits in the evolution of menopause.The study investigates the evolution of menopause in toothed whales, a unique opportunity to understand the adaptive value of menopause in a comparative context. Toothed whales are the only mammal taxon where menopause has evolved multiple times, providing a rich dataset for analysis. The researchers used Bayesian mortality models and ovarian corpora data to estimate lifespan and reproductive lifespan for 32 species of toothed whales. They found that menopause evolved in these whales by extending their total lifespan without increasing their reproductive lifespan, supporting the 'live-long' hypothesis. Additionally, they showed that menopause allows females to increase their lifespan overlap with their grandoffspring and offspring without increasing their reproductive overlap with their daughters, enhancing intergenerational help. These findings are consistent with the evolutionary theories of ageing and suggest that the same pathways that led to menopause in humans can also explain its evolution in toothed whales. The study also highlights the importance of intergenerational help and the balance between reproductive and non-reproductive benefits in the evolution of menopause.