Kristian Beedholm

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Echolocating toothed whales produce high-powered clicks by pneumatic actuation of phonic lips in their nasal complexes. All non-physeteroid toothed whales have two pairs of phonic lips allowing many of these species to produce both whistles and clicks at the same time. That has led to the hypothesis that toothed whales can increase the power outputs and(More)
Toothed whales depend on echolocation for orientation and prey localization, and source parameters of echolocation clicks from free-ranging animals therefore convey valuable information about the acoustic physiology and behavioral ecology of the recorded species. Recordings of wild hourglass (Lagenorhynchus cruciger) and Hector's dolphins (Cephalorhynchus(More)
An increasing number of smaller odontocetes have recently been shown to produce stereotyped narrow-band high-frequency (NBHF) echolocation clicks. Click source parameters of NBHF clicks are very similar, and it is unclear whether the sonars of individual NBHF species are adapted to specific habitats or the presence of other NBHF species. Here, we test(More)
Visually dominant animals use gaze adjustments to organize perceptual inputs for cognitive processing. Thereby they manage the massive sensory load from complex and noisy scenes. Echolocation, as an active sensory system, may provide more opportunities to control such information flow by adjusting the properties of the sound source. However, most studies of(More)
Toothed whales produce sound in their nasal complex by pneumatic actuation of phonic lip pairs within the blowhole. It has been hypothesized that dual actuation of the phonic lip pairs can generate two pulses that merge to form a single echolocation click with a higher source level, broader bandwidth and larger potential for beam steering than if produced(More)
The delay jitter discrimination threshold in bats is a disputed subject. Some investigators have obtained results indicating that bats are able to discriminate alternations in delay down to 10 ns, which appears incredible for purely physical reasons. Using actual bat echolocation sequences recorded during an easy detection task to measure simulated delay(More)
The Indian Ocean and Atlantic bottlenose dolphins (Tursiops aduncus and Tursiops truncatus) are among the best studied echolocating toothed whales. However, almost all echolocation studies on bottlenose dolphins have been made with captive animals, and the echolocation signals of free-ranging animals have not been quantified. Here, biosonar source(More)
The biosonar pulses from free-ranging northern bottlenose whales (Hyperoodon ampullatus) were recorded with a linear hydrophone array. Signals fulfilling criteria for being recorded close to the acoustic axis of the animal (a total of 10 clicks) had a frequency upsweep from 20 to 55 kHz and durations of 207 to 377 μs (measured as the time interval(More)
A key component in the operation of a biosonar system is the radiation of sound energy from the sound producing head structures of toothed whales and microbats. The current view involves a fixed transmission aperture by which the beam width can only change via changes in the frequency of radiated clicks. To test that for a porpoise, echolocation clicks were(More)
Bottlenose dolphins (Tursiops sp.) depend on frequency-modulated whistles for many aspects of their social behavior, including group cohesion and recognition of familiar individuals. Vocalization amplitude and frequency influences communication range and may be shaped by many ecological and physiological factors including energetic costs. Here, a calibrated(More)