Humpback whale adult females and calves balance acoustic contact with vocal crypsis during periods of increased separation
Abstract Acoustic communication is important for animals with dependent young, particularly when they are spatially separated. Maternal humpback whales (Megaptera novaeangliae) use acoustic calling to help minimize the risk of separation from their young calves during migration. These pairs also use...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Wiley
2022-02-01
|
| Series: | Ecology and Evolution |
| Subjects: | |
| Online Access: | https://doi.org/10.1002/ece3.8604 |
| _version_ | 1818532783259123712 |
|---|---|
| author | Katherine L. Indeck Michael J. Noad Rebecca A. Dunlop |
| author_facet | Katherine L. Indeck Michael J. Noad Rebecca A. Dunlop |
| author_sort | Katherine L. Indeck |
| collection | DOAJ |
| description | Abstract Acoustic communication is important for animals with dependent young, particularly when they are spatially separated. Maternal humpback whales (Megaptera novaeangliae) use acoustic calling to help minimize the risk of separation from their young calves during migration. These pairs also use acoustic crypsis to minimize detection by males. How they balance a restricted active space with the need to maintain acoustic contact during periods of separation is not yet understood. Here, we analyzed movement metrics of tagged adult female–calf pairs during migration to identify two behavioral states, “resting/milling” and “travelling.” When travelling, these pairs dived synchronously and exhibited little to no spatial separation. Alternatively, adult females had significantly longer dive durations (p < .01) when resting, and while they spent prolonged times at depth, calves would surface several times independently. This demonstrated that these pairs are frequently separated during periods of rest. We then determined whether the call rates and acoustic levels of these pairs increased with more frequent separation, finding that both adult females and calves significantly increased their call rates, but not levels, when resting. We also found that adult female–calf pairs have a restricted active space, with less than 15% of calls estimated to be detectable beyond 2 km. However, as with call level, detection distance did not differ significantly between the two behavioral states. In summary, adult female–calf pairs maintain successful communication during periods of separation by calling more frequently rather than by producing louder calls. This strategy aids in maintaining acoustic contact while simultaneously limiting detectability by conspecifics. |
| first_indexed | 2024-12-11T17:50:02Z |
| format | Article |
| id | doaj.art-52592d6d683a49109d275618f852f1cc |
| institution | Directory Open Access Journal |
| issn | 2045-7758 |
| language | English |
| last_indexed | 2024-12-11T17:50:02Z |
| publishDate | 2022-02-01 |
| publisher | Wiley |
| record_format | Article |
| series | Ecology and Evolution |
| spelling | doaj.art-52592d6d683a49109d275618f852f1cc2022-12-22T00:56:14ZengWileyEcology and Evolution2045-77582022-02-01122n/an/a10.1002/ece3.8604Humpback whale adult females and calves balance acoustic contact with vocal crypsis during periods of increased separationKatherine L. Indeck0Michael J. Noad1Rebecca A. Dunlop2Cetacean Ecology and Acoustics Laboratories School of Veterinary Science University of Queensland Gatton Queensland AustraliaCetacean Ecology and Acoustics Laboratories School of Veterinary Science University of Queensland Gatton Queensland AustraliaCetacean Ecology and Acoustics Laboratories School of Veterinary Science University of Queensland Gatton Queensland AustraliaAbstract Acoustic communication is important for animals with dependent young, particularly when they are spatially separated. Maternal humpback whales (Megaptera novaeangliae) use acoustic calling to help minimize the risk of separation from their young calves during migration. These pairs also use acoustic crypsis to minimize detection by males. How they balance a restricted active space with the need to maintain acoustic contact during periods of separation is not yet understood. Here, we analyzed movement metrics of tagged adult female–calf pairs during migration to identify two behavioral states, “resting/milling” and “travelling.” When travelling, these pairs dived synchronously and exhibited little to no spatial separation. Alternatively, adult females had significantly longer dive durations (p < .01) when resting, and while they spent prolonged times at depth, calves would surface several times independently. This demonstrated that these pairs are frequently separated during periods of rest. We then determined whether the call rates and acoustic levels of these pairs increased with more frequent separation, finding that both adult females and calves significantly increased their call rates, but not levels, when resting. We also found that adult female–calf pairs have a restricted active space, with less than 15% of calls estimated to be detectable beyond 2 km. However, as with call level, detection distance did not differ significantly between the two behavioral states. In summary, adult female–calf pairs maintain successful communication during periods of separation by calling more frequently rather than by producing louder calls. This strategy aids in maintaining acoustic contact while simultaneously limiting detectability by conspecifics.https://doi.org/10.1002/ece3.8604acoustic crypsisactive spacebehavioral statescommunication strategycontact callinghumpback whales |
| spellingShingle | Katherine L. Indeck Michael J. Noad Rebecca A. Dunlop Humpback whale adult females and calves balance acoustic contact with vocal crypsis during periods of increased separation Ecology and Evolution acoustic crypsis active space behavioral states communication strategy contact calling humpback whales |
| title | Humpback whale adult females and calves balance acoustic contact with vocal crypsis during periods of increased separation |
| title_full | Humpback whale adult females and calves balance acoustic contact with vocal crypsis during periods of increased separation |
| title_fullStr | Humpback whale adult females and calves balance acoustic contact with vocal crypsis during periods of increased separation |
| title_full_unstemmed | Humpback whale adult females and calves balance acoustic contact with vocal crypsis during periods of increased separation |
| title_short | Humpback whale adult females and calves balance acoustic contact with vocal crypsis during periods of increased separation |
| title_sort | humpback whale adult females and calves balance acoustic contact with vocal crypsis during periods of increased separation |
| topic | acoustic crypsis active space behavioral states communication strategy contact calling humpback whales |
| url | https://doi.org/10.1002/ece3.8604 |
| work_keys_str_mv | AT katherinelindeck humpbackwhaleadultfemalesandcalvesbalanceacousticcontactwithvocalcrypsisduringperiodsofincreasedseparation AT michaeljnoad humpbackwhaleadultfemalesandcalvesbalanceacousticcontactwithvocalcrypsisduringperiodsofincreasedseparation AT rebeccaadunlop humpbackwhaleadultfemalesandcalvesbalanceacousticcontactwithvocalcrypsisduringperiodsofincreasedseparation |