Exfoliating Whales–Sandy Bottom Contact Behaviour of Humpback Whales

Abstract

Cetaceans are known for their intelligence and display of complex behaviours including object use. For example, bowhead whales (Balaena mysticetus) are known to rub on rocks and some humpback whale (Megaptera novaeangliae) populations undertake lateral bottom feeding. Such underwater behaviour is difficult to observe but can play a critical role in the whales’ survival and well-being. Distinguishing social behaviours from those which serve a specific function remains challenging due to a lack of direct observations and detailed descriptions of such behaviours. A CATS (Customized Animal Tracking Solutions) suction cup tag with on board video and a 3D inertial measurement unit was deployed on three different humpback whales to assess their behaviour in the Gold Coast bay, Australia. Here, we present evidence of humpback whales (tagged and untagged individuals) performing bottom contact with prolonged rolling on sandy substrate. In addition, we showed that fish were actively feeding from the whales’ skin during this behaviour. We detail the behaviour and discuss possible drivers, with a focus on cetacean innovation, possible ectoparasite removal, and habitat preferences.

The First Report of Pennella (Crustacea: Copepoda) Infesting Stenella coeruleoalba Stranded in Malta: Morphological and Genetic Analyses

“…Furthermore, the presence of a wound or ulceration on the lower right side suggests that either the dolphin may have engaged in rubbing itself against substrates to remove parasites or that the heavy load of this large parasite in this area together with any other underlying infection may have caused ulceration. In this regard, bottom contact behavior has been recorded in some cetacean species [19,[43][44][45].…”

“…Elevated infestations are often linked to underlying health conditions, such as immunosuppression related to viral infections or heavy loads of pollutants [8,17,18]. Consequently, monitoring for Pennella infestations can provide valuable insights into the health status of cetacean populations [19,20]. In the Mediterranean, such efforts play a crucial role in effective conservation strategies, especially in the context of various international agreements and protocols, such as ACCOBAMS [21], SPA/BD Protocol [22], CITES [23], and CMS [24], which emphasize the importance of monitoring, protecting, and conserving cetaceans [25][26][27].…”

Brushes and Shelters as Low-Cost Environmental Enrichment Devices for Loggerhead Turtles (Caretta caretta) During Rehabilitation

“…A widespread conservation intervention for sea turtles is to treat injured or diseased animals at rehabilitation centers (Ullmann and Stachowitsch 2015;Monreal-Pawlowsky et al 2017). Recovery may take several years, so efforts to improve the welfare of animals during rehabilitation is of prime importance.…”

“…Food provisioning in PVC pipes or other EEDs also led to a reduction in stereotyped swimming in green and loggerhead turtles (Caretta caretta) reared in captivity (Therrien et al 2007). The use of nutritional enrichment (including crabs and jellyfish) has been proposed to encourage natural feeding behavior in loggerhead turtles (Monreal-Pawlowsky et al 2017).…”

“…It has been proposed that this scratching allows the turtle to remove epibionts (Frick and McFall 2007). Scratching may also be desirable to remove dead skin, as is the case in many other vertebrates (Meynecke et al 2023). The sensation of scratching may activate the neural reward pathways (Martínez-García and Lanuza 2018).…”