Diurnal activity in the Samoan flying fox, Pteropus samoensis

C Thomson, A P Brooke, John Roger Speakman

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


Speakman and co-workers suggested the diurnal Samoan flying fox, Pteropus samoensis, may be at risk of hyperthermia when flying during the day, particularly at high levels of insolation. We monitored activity of this bat and climate simultaneously at two different sites and four times of year in American Samoa. Flight activity varied significantly with time of day, between days, study sites and seasons. Out of the six data sets collected, the four with the highest mean levels of insolation showed a significant decrease in bat numbers with increasing temperature and sunlight. When each individual activity count was directly compared to the predict-ions of Speakman and co-workers' biophysical model, 85-95% of bat flight activity was found to be in conditions the model suggested would not pose a risk of hyperthermia. This supports the suggestion that in extreme conditions the animals would not fly as they risked overheating. The 5-15% of counts in which animals were seen to fly in conditions the model predicted they should not may be explained by erroneous assumptions underlying the model predictions.

Original languageEnglish
Pages (from-to)1595-1606
Number of pages12
JournalPhilosophical Transactions of the Royal Society of London. Series B: Biological sciences
Issue number1375
Publication statusPublished - 29 Oct 1998


  • Pteropus samoensis
  • hyperthermia
  • diurnality
  • flight
  • American-Samoa
  • bats
  • populations
  • behavior


Dive into the research topics of 'Diurnal activity in the Samoan flying fox, Pteropus samoensis'. Together they form a unique fingerprint.

Cite this