Pedersen Michael B.

No Thumbnail Available
Last Name
Pedersen
First Name
Michael B.
ORCID

Filters

2019 - 2020 2
2
2
Reset filters

Settings

Search Results

Now showing 1 - 2 of 2
  • Article
    Response to: the metabolic cost of whistling is low but measurable in dolphins
    (Company of Biologists, 2020-06-08) Pedersen, Michael B. ; Fahlman, Andreas ; Borque-Espinosa, Alicia ; Madsen, Peter T. ; Jensen, Frants H.
    Costs of sound production have been investigated only sparsely incetaceans, despite recent efforts to understand how increasinganthropogenic noise affects these animals that rely extensively onsound for communication and foraging. Theoretical estimates suggestthat metabolic costs of whistling for bottlenose dolphins should be<0.54% of resting metabolic rate (RMR) (Jensen et al., 2012),whereas empirical studies of a single whistling dolphin surprisinglyclaimed that sound production costs were around 20% of RMR (Holtet al., 2015; Noren et al., 2013). Addressing this discrepancy, wefound that costs of whistling were significantly less than 20% RMRand not statistically different from theoretical estimates (Pedersenet al., 2020). In their correspondence, Noren et al., 2020 argue thatthey did not claim whistling was‘costly’and questioned aspects ofour methods, and we address these points here.
  • Article
    Whistling is metabolically cheap for communicating bottlenose dolphins (Tursiops truncatus)
    (Company of Biologists, 2019-12-03) Pedersen, Michael B. ; Fahlman, Andreas ; Borque-Espinosa, Alicia ; Madsen, Peter T. ; Jensen, Frants H.
    Toothed whales depend on sound for communication and foraging, making them potentially vulnerable to acoustic masking from increasing anthropogenic noise. Masking effects may be ameliorated by higher amplitudes or rates of calling, but such acoustic compensation mechanisms may incur energetic costs if sound production is expensive. The costs of whistling in bottlenose dolphins (Tursiops truncatus) have been reported to be much higher (20% of resting metabolic rate, RMR) than theoretical predictions (0.5–1% of RMR). Here, we address this dichotomy by measuring the change in the resting O2 consumption rate (V̇O2), a proxy for RMR, in three post-absorptive bottlenose dolphins during whistling and silent trials, concurrent with simultaneous measurement of acoustic output using a calibrated hydrophone array. The experimental protocol consisted of a 2-min baseline period to establish RMR, followed by a 2-min voluntary resting surface apnea, with or without whistling as cued by the trainers, and then a 5-min resting period to measure recovery costs. Daily fluctuations in V̇O2 were accounted for by subtracting the baseline RMR from the recovery costs to estimate the cost of apnea with and without whistles relative to RMR. Analysis of 52 sessions containing 1162 whistles showed that whistling did not increase metabolic cost (P>0.1, +4.2±6.9%) as compared with control trials (−0.5±5.9%; means±s.e.m.). Thus, we reject the hypothesis that whistling is costly for bottlenose dolphins, and conclude that vocal adjustments such as the Lombard response to noise do not represent large direct energetic costs for communicating toothed whales.