Subsurface swimming and stationary diving are metabolically cheap in adult Pacific walruses (Odobenus rosmarus divergens).
J Exp Biol
; 224(23)2021 12 01.
Article
in En
| MEDLINE
| ID: mdl-34746957
ABSTRACT
Walruses rely on sea-ice to efficiently forage and rest between diving bouts while maintaining proximity to prime foraging habitat. Recent declines in summer sea ice have resulted in walruses hauling out on land where they have to travel farther to access productive benthic habitat while potentially increasing energetic costs. Despite the need to better understand the impact of sea ice loss on energy expenditure, knowledge about metabolic demands of specific behaviours in walruses is scarce. In the present study, 3 adult female Pacific walruses (Odobenus rosmarus divergens) housed in professional care participated in flow-through respirometry trials to measure metabolic rates while floating inactive at the water surface during a minimum of 5â
min, during a 180 s stationary dive, and while swimming â¼90â
m horizontally underwater. Metabolic rates during stationary dives (3.82±0.56â
lâ
O2â
min-1) were lower than those measured at the water surface (4.64±1.04â
lâ
O2â
min-1), which did not differ from rates measured during subsurface swimming (4.91±0.77â
lâ
O2â
min-1). Thus, neither stationary diving nor subsurface swimming resulted in metabolic rates above those exhibited by walruses at the water surface. These results suggest that walruses minimize their energetic investment during underwater behaviours as reported for other marine mammals. Although environmental factors experienced by free-ranging walruses (e.g. winds or currents) likely affect metabolic rates, our results provide important information for understanding how behavioural changes affect energetic costs and can be used to improve bioenergetics models aimed at predicting the metabolic consequences of climate change on walruses.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Walruses
/
Diving
Type of study:
Prognostic_studies
Limits:
Animals
Language:
En
Journal:
J Exp Biol
Year:
2021
Document type:
Article
Affiliation country:
Spain