Care and Enrichment for Captive Cephalopods

A natural constant predicts survival to maximum age

Information about the survival of species is important in many ecological applications. Yet, the estimation of a species' natural mortality rate M remains a major problem in the management and conservation of wild populations, often circumvented by applying empirical equations that relate mortality to other traits that are more easily observed. We show that mean adult M can be approximated from the general law of decay if the average maximum age reached by individuals in a cohort is known. This is possible because the proportion P of individuals surviving to the average maximum age in a cohort is surprisingly similar across a wide range of examined species at 1.5%. The likely reason for the narrow range of P is a universal increase in the rate of mortality near the end of life, providing strong evidence that the evolutionary theories of ageing are the norm in natural populations.

Why Are Octopuses Going to Be the 'Poster Child' for Invertebrate Welfare?

Animal welfare consideration and actions are generally addressed to animals similar to us, predominantly large mammals. Invertebrates are neglected partly because they are unknown, though new exploration of the oceans has helped with this. Also, we know little about their ecology and welfare. This is gradually changing, and the octopuses are likely to be the first beneficiaries. Scientists are finding that cephalopods are far more intelligent than we thought, with the Cambridge Declaration of Consciousness suggesting they might possess this quality of mind. Partly as a result, the European Union has described and demanded good care for cephalopods such as the octopus in captivity. Public opinion has been swayed to approval by anecdotes of octopuses doing unusual actions, and by several recent books pointing out interesting and intelligent behavior of cephalopods. Aquariums have begun to feature octopuses for them. With this progress, welfare of invertebrate animals has begun to matter. While the octopuses will be the first animal group to benefit, they may pave the way for us to see that different does not mean unworthy of regard and welfare consideration.