Acoustic telemetry showed that stomach temperature from large bluefin tuna, Thunnus thynnus, held in an impoundment, changes markedly during feeding. The stomach cools rapidly on ingesting cold food. It then warms to a maximum of 10–15 °C above water temperature over a period of 12–20 h. Temperature decreases slowly over the next 20–30 h to a final state where it remains 3–6 °C above water temperature. The viscera are thermally isolated. Conductive heat losses are reduced by an overlying gas bladder and by the thick fatty muscle of the body wall. Convective heat losses are prevented by heat exchangers in the circulation. The temperature rise can be accounted for by heat released in the hydrolytic processes of digestion and by an increase in metabolic rate. The elevated temperatures should speed digestion and allow the tuna to feed frequently when food is abundant.
In the field: an interview with Sönke Johnsen
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Sönke Johnsen is a Professor at Duke University, USA, investigating visual ecology and he talks about his experiences of collecting transparent animals while blue water diving and in a submersible, as well as outrunning Hurricane Katrina.
Call for new preLighters
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preLights is the preprint highlighting community supported by The Company of Biologists. At the heart of preLights are our preLighters: early-career researchers who select and write about interesting new preprints for the research community. We are currently looking for new preLighters to join our team. Find out more and apply here.
Graham Scott in conversation with Big Biology
Graham Scott talks to Big Biology about the oxygen cascade in mice living on mountaintops, extreme environments for such small organisms. In this JEB-sponsored episode, they discuss the concept of symmorphosis and the evolution of the oxygen cascade.
Cleaner fish are potential super-spreaders
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Bluestreak cleaner wrasse spend their days pecking parasites off the skins of other fish, but now Pauline Narvaez & co have found that they may also be inadvertent super-spreaders. Parasitic flatworms can hitch a ride on the cleaners to reach their next host.
Hearing without a tympanic ear
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In their Review, Grace Capshaw, Jakob Christensen-Dalsgaard and Catherine Carr explore the mechanisms of hearing in extant atympanate vertebrates and the implications for the early evolution of tympanate hearing.
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