From 1 - 6 / 6
  • Recordings were made of adult male and female Weddell seals on the ice during the breeding seasons of 1990 and 1997. The recordings were made near Davis, Antarctica in the Vestfold Hills. The vocalisations made with both the mouth and nostrils closed were classified into call types. These call types are also produced by the seals when underwater. The call classifications were based on those described by Thomas, J.A. and Kuechle,, V.B. (1982, J. Acoust. Soc. Amer. 72: 1730-1738) and Pahl, B.C., Terhune, J.M. and Burton, H.R. (1997, Aus. J. Zool. 45: 171-187). Nineteen call types were identified. Of these, males made 18 and females made 15. Trills are only made by males and it is likely that a stepped ascending whistle is only made by females. A roar and mew are also potential male-only call types. The data suggest that the Trill vocalisations can be used to indicate the presence of males. This will be useful when recording underwater where the calling seals cannot be observed directly. A description of the types of calls made by Weddell Seals is listed below. SymbolNameDescription OToneConstant-frequency, predominantly sinusoidal call. LGrowlConstant-frequency, broad bandwidth, long call. QWhoopConstant-frequency call with a terminal upsweep. SSqueakBrief call with constant frequency or rising frequency and an irregular waveform. WAWhistle AscendingAscending frequency, sinusoidal waveform. TCTrill Constant-FrequencyNarrow bandwidth trill with a constant-frequency beginning, sinusoidal or frequency-modulated waveform. TTrillNarrow to broad bandwidth, containing a frequency downsweep, greater than 2 seconds. WDWhistle DescendingDescending frequency, sinusoidal waveform (less than 2 seconds). MMewAbruptly descending frequency followed by a long constant-frequency ending. CChugAbruptly descending frequency followed by a brief constant-frequency ending. GGuttural Glug (Grunt)Descending-frequency call that was lower than a Chug and had a brief duration. WAGWhistle Ascending - GruntBrief Ascending Whistle followed by a Guttural Glug (Grunt), the two types alternate in a regular pattern. KKnockAbrupt, brief-duration broadband sound

  • From the abstract of the attached paper: Underwater calling behaviour between breathing bouts of a single adult male Weddell seal (Leptonychotes weddellii) was examined with respect to call type and timing late in the breeding season at Davis Station, Antarctica. Underwater calls and breathing sounds were recorded on 1 and 8 December 1997. Thirty-seven sequences of calls prior to surfacing to breathe and 36 post-submerging sets of calls were analysed with respect to probability of call type occurrence and timing. Dives were 461 plus or minus 259 seconds (mean plus or minus standard deviation). The seal called every 29.7 plus or minus 56.2 seconds throughout a dive. The first call after submerging was usually (n = 29 of 36) a low frequency (less than 0.8 kHz) growl. Three patterns of three- to five-call type sequences were made following 28 of 36 breathing bouts. Call type patterns after submerging exhibited fewer different sequences than those before surfacing (chi-squared = 61.42, DF = 4, p less than 0.000001). The call usage patterns before surfacing were diverse and did not indicate when the seal was going to surface, a time when he would be vulnerable to attack from below. Our findings suggest the hypotheses that territorial male Weddell seals call throughout each dive and use stereotyped call patterns to identify themselves while vocally asserting dominance. This work was completed as part of ASAC project 2122 (ASAC_2122). The fields in this dataset are: Tape number Sequence per tape Sequence entire data Call types Count since last breath Last breathing bout number Count prior to next breath Time in tape (seconds) End time of last breath Start time of next breath Time since dive The 'sequence' relates to the sequence of call types that are given between the end of the last breath of a breathing bout and the beginning of the first breath the next time the seal surfaces to breathe. Essentially the report relates to the stereotyped nature of the call types, especially just after the dominant male dives after finishing breathing. Each time the animal surfaced, that was identified as a breathing bout. They are numbered sequentially. At the very start of the data set the seal had to surface before the breathing bout could be counted (as number 1). This procedure enabled us to identify the order and timing of the calls that occurred immediately before and immediately after each breathing bout. Thus, the 'count prior to the next breath' gives the order of the calls before the seal surfaced to breathe again (third last, second last, last,). The call types were analysed with respect to the following pattern: third last, second last, last, breathing bout, first, second, third, etc. to third last, second last, last, next breathing bout.

  • From the abstract of the attached paper: Vocal recognition may function as a critical factor in maintaining the phocid mother-pup bond during lactation. For vocal recognition to function, the caller must produce individually distinct calls that are recognised by their intended recipient. Mother-pup vocal recognition has been studied extensively in colonial otariids and appears to be characteristic of this family. Although less numerous, empirical studies of phocid species have revealed a range of recognition abilities. This study investigated whether Weddell seal (Leptonychotes weddellii) females produce individually distinct 'pup contact' calls that function during natural pair reunions. Fifteen calls from each of nine females recorded in the Vestfold Hills, Antarctica were analysed. One temporal, nine fundamental frequency and five spectral characteristics were measured. Results of the cross-validated Discriminant Function Analysis revealed that mothers produce individually distinct calls with 56% of calls assigned to the correct individual. The probability of achieving this level of discrimination on novel data by chance alone is highly improbable. Analysis of eight mother-pup reunions recorded near McMurdo Sound, Antarctica further demonstrated that these 'pup contact' calls function during natural pair reunions. Behavioural analysis also revealed that pups were chiefly responsible for establishing and maintaining close contact throughout the reunion process. Our study therefore demonstrates that Weddell seal females produce calls with sufficient stereotypy to allow pups to identify them during pair reunions, providing evidence of a functioning mother-pup vocal recognition system. Column A - Row 1: Gives the tag number of the female. - Rows 3-33: The list of acoustic measurements recorded from the spectrograms. - Rows 3-5: Temporal measurements recorded in milliseconds. - Rows 7-12: Frequency measurements recorded from the fundamental frequency. Rows 9-11 were measured at the 1/4, 2/4 and 3/4 temporal positions along the fundamental frequency respectively. - Rows 13-17: Give the number of the frequency band with the most energy at the temporal positions stated (i.e. fundamental frequency band=1, first harmonic=2 etc). - Rows 19-29: List the fundamental frequency measurements, taken at the temporal positions stated, used to calculate Mean frequency (Row 31) and the Coefficient of Frequency Modulation (Row 33) using the formula listed in the publication. - Rows 35 and 36: List the cursor error margins of the acoustic analysis program I used. Columns B-P - Give details of the above mentioned acoustic characteristics for 15 replicate calls from each of the 9 females sampled.

  • Possible communication between territorial male Weddell seals (Leptonychotes weddellii) under the ice with females on the ice was investigated. In-air and underwater recordings of underwater calls were made at three locations near Davis, Antarctica. Most underwater calls were not detectable in air, often because of wind noise. In-air call amplitudes of detectable calls ranged from 32-74 dB re. 20 microPa at 86 Hz down to 4-38 dB re. 20 microPa at 3.6 kHz. Most of these would be audible to humans. Only 26 of 582 amplitude measurements (from 230 calls) ranged from 5 dB to a maximum of 15 dB above the minimum harbour-seal (Phoca vitulina) in-air detection threshold. Seals on the ice could likely hear a few very loud underwater calls but only if the caller was nearby and there were no wind noises. The low detectability of underwater calls in air likely precludes effective communication between underwater seals and those on the ice. See other metadata records and datasets associated with ASAC project 2122 (ASAC_2122) for further information. The fields in this dataset are: Column A: G = grunt, T = trill, CT = constant freq. trill, O = tone, C = chug, AW = ascending whistle, DW = descending whistle, L = growl, R - roar Column B: frequency (Hz) Column C: underwater call level NOTE dB re 20 uPa Column D: in-air call level dB re 20 uPa Column E: in-air background noise level at this frequency dB re 20 uPa Column F: water - air difference dB Column G: location, 1-3, see paper for code Column H: seal in-air threshold dB re 20 uPa Column I: human in-air threshold dB re 20 uPa Column J: seal in-air threshold at this frequency dB re 20 uPa

  • Many vocalisations produced by Weddell seals (Leptonychotes weddellii) are made up of repeated individual distinct sounds (elements). Patterning of multiple element calls was examined during the breeding season at Casey and Davis, Antarctica. Element and interval durations were measured from 405 calls all greater than 3 elements in length. The duration of the calls (22 plus or minus 16.6s) did not seem to vary with an increasing number of elements (F4.404 = 1.83, p = 0.122) because element and interval durations decreased as the number of elements within a call increased. Underwater vocalisations showed seven distinct timing patterns of increasing, decreasing, or constant element and interval durations throughout the calls. One call type occurred with six rhythm patterns, although the majority exhibited only two rhythms. Some call types also displayed steady frequency changes as they progressed. Weddell seal multiple element calls are rhythmically repeated and thus the durations of the elements and intervals within a call occur in a regular manner. Rhythmical repetition used during vocal communication likely enhances the probability of a call being detected and has important implications for the extent to which the seals can successfully transmit information over long distances and during times of high level background noise. See other metadata records and datasets associated with ASAC project 2122 (ASAC_2122) for further information. The fields in this dataset are: Tape/Site/File Filename Call Type Total Number of Elements Attribute Frequency Time Casey Davis

  • 2000/2001 season 31 quad based surveys were conducted along the pack-ice edge to identify where leopard seals could be accessed. 31 one hour aerial surveys were also conducted to identify the position and number of seals in the region. 36 boat based surveys were conducted to identify the size and sex of leopard seals, whether they were a resight and the possibility of sedating seals. There were a total of 23 leopard seal captures. Resights from the 1999/2000 season were made of 5 known seals. Samples were collected from a total of 19 known and 20 unknown leopards seals. Samples were also collected from 14 known weddell seals. All blood, fur, whisker, scat, and morphmetric measurements were collected. Three satellite tracking units were deployed following the moult on adult leopard seals, and one crittercam unit. 14 blood samples were taken from leopard seals, 13 blood samples from weddell seals. 6 blubber samples from leopard seals, 17 fur samples from leopard seals and 7 whiskers from leopard seals and 2 from weddell seals 32 scats from leopard seals, 50 urine and 30 scat samples from weddell seals. Voucher samples for stable isotope analysis from 2 weddell seals, 26 penguins and 64 fish were collected. Spatial movements and haul out data from 11 leopard seals has been analysed. The blood, skin muscle, whisker, fat and fur has been prepared for later analysis. 42 separate scats have been analysed to determine diet composition. The captive feeding trials have been performed using two captive leopard seals. For each seal the following tests have been conducted, biochemical analysis of fresh serum, manual packed cell volme and white cell counts and differential white cell counts from blood smears and all haematological analysis. The refinement of the anaesthetic protocol of Zolazepam/ Tiletamine in leopard seals has been continued and this combination appears to provide a deeper and more reliable level of immobilisation compared with other anaesthetic combinations to date. 2001/2002 season In the Prydz Bay area, 28 one-hour aerial surveys were conducted by Squirrel helicopter, 23 quad based surveys and 12 boat based surveys were conducted between latitudes 68 degrees 20'S and 68 degrees 40'S along the fast ice edge to identify the position and number of leopard seals in the region. 110 leopard seals were sighted overall and of those 5 were positively identified as resight animals, tagged during previous seasons. Five leopard seal capture procedures were performed and postmortem samples, blood fur, blubber, skin, whiskers, scats, urine and morphometric measurements were collected from two leopard seals. 6 urine and 15 scat samples collected from known and unknown leopard seals and 7 fur samples including 2 from resight animals tagged during the previous two seasons. Three Weddell seal capture procedures were performed and blood samples were collected from each seal. 125 weddell seal urine and 112 weddell seal scat samples were also collected. For stable isotope and signature fatty acid analysis, the following samples were collected as voucher samples; 1 weddell seal muscle sample, 3 adelie penguin muscle samples, 1 elephant seal whisker, muscle and skin sample, 73 Antarctic cod muscle samples, 23 ice fish and 20 krill. Foraging Information Scats collected from 20 seals and will be analysed for diet information. Stable isotope analysis involved fur, blood and whiskers collected from 35 animals. A key to the stable isotopes is provided in the download file. Fatty acid analysis involved collection of blubber from 35 animals. The fields in this dataset are: Spatial Data Seal Id: adult female Ptt tag number Date: date data collected Time: time data collected Location Class: ARGOS location classes 3 (0-150m), 2 (150-350m) and 1 (350-1000m). South: latitude decimal degrees East: longitude decimal degrees Amphipods ID = ID of seal from which scat sample collected Length = length of amphipod Wt = weight of amphipod Species = species of amphipod broken specimens = not whole specimens. Otolith data; No = number collected Species = species of fish identified from otolith Length/breadth/width = measurements of otolith in mm Eqn = calculation used to determine Standard length of fish from otolith size Mass = mass calculation of fish from otolith measurements Age and Length classes = size of mass of fish classified into groups Fatty acids Ret Time = retention time of individual fatty acid Area counts = TBA Area % = TBA LS Scat ID refers to the Identification number we gave to each seal. U refers to a unknown seal Date = date sample collected Sex = sex of seal Age = juvenile, sub adult or adult Seal = seal fur found in scat penguin = penguin remains found in scat and so on for each other column including fish, otolith, krill rocks, amphipod and seaweed. St weight refers to stomach weight.