ResultsGorgoning behaviour: during each rubbing bout the individual either rubs its ventral, lateral or dorsal body part on the gorgoni-an. This is often repeated so that all body areas are rubbed (Fig.2 (1-6)). When in group, dolphins queue up behind each other to wait for their next approach (Fig.3 (1-2)).♦ 29 gorgoning events of a total of 351 surveys between October
2009 - December 2012♦ It is widespread: 44 different individuals of a population of 119♦ It is selective: only seen for Rumphella aggregata (Fig.4)♦Mostlydonebyadults(Fig.5);nosignificantdifferencebetween
sexes (X²= 0.38, df =1, P<0.538) ♦ Observed during the routine of resting bouts in critical habitats
such as Fanous Reef and Shaab El Erg (Fig.6)
IntroductionSeveral hypotheses have been proposed concerning the functio-nal role of self-rubbing or object rubbing in odontocetes. These include hygiene (e.g. ectoparasite removal), sensual pleasure, playandsocializingactivity.Indo-Pacificbottlenosedolphins(Tur-siops aduncus) off Hurghada, Northern Red Sea, Egypt (Fig.1) are observed rubbing on gorgonians (Rumphella aggregata).
Self-rubbing behaviour on gorgonians(Rumphella aggregata) in Indo-Pacific bottlenose dolphins (Tursiops aduncus)off Hurghada, Northern Red Sea, Egypt
Angela Ziltener1,2 and Sina Kreicker1,2
(1) Anthropological Institute and Museum, University of Zurich, Switzerland(2) Dolphin Watch Alliance, Switzerland
B02
MethodsThe worldwide unique boat and underwater based methodolo-gy allows us observations impossible to monitor otherwise. Dol-phinsarefirstobservedfromtheboatandsurveyedfor5minutesad libitum. In appropriate situations, a minimum of two scuba divers join the dolphins underwater and conduct a group follow with the aid of video recordings. Additionally, photographs for genderidentificationandageclassificationaretaken.
Discussion♦ We hypothesize that gorgonian-rubbing represents prophylactic or even therapeutic self-medication.
Previous studies show that other species of the genus Rumphella possess antibacterial and antifungal properties.
♦ Gorgoning may be a cultural behaviourFuture work will test these hypotheses
Implements:♦ Underwater surveys show great promise in revealing rich/complex/unexpected dolphin behaviour♦ ConservationimplementationsarenecessarytoprotectcriticalhabitatsfortheIndo-Pacificbottlenose
dolphin in the Hurghada area from human threatsAcknowledgements WethankProf.Dr.CarelvanSchaik,Dr.MichaelKrützenandCorinneAckermannforscientificadvice.Specialthankstotheco-founderofthedolphinprojectinHurghadaMichaelStadermannwhogivesustechnicalandfinancialsupportandallhisunderwaterfilmmaterialfordataanalyses.WearegratefultoallmembersofDolphinWatchAllianceandOceanCare,particularlyforfinancialsupport.ThankyouIwetaPriedeforthegraphicdesignanddataanalysesandMarcusGisiforbuildingupadatabase.BigthankstotherestoftheSWDFteam Sandra Caramelle and Tim Windhorn for technical support and help in data collection. Thank you Ahmed Sala und Ahmed Aboushora for technical support on the boat and Dr. Nasser Elomda for administrative work. Thanks to HEPCA for the cooperation and support in Hurghada, Egypt.
Angela Ziltener
Fig.1: Study site off Hurghada, Northern Red Sea, Egypt
Fig.2(1-6):AmaleIndo-Pacificbottlenosedolphinrubson a gorgonian coral in Fanous, Hurghada, Egypt.
Fig.5: Age structure of gorgoning individuals
Fig.6:Gorgoningeventsare significantlymoreobser-ved during resting bouts (X²= 12.46, df =2, P<0.002)
Fig.3 (1-2): Dolphins wait for their turn and queue up behind their group members. Fig.4: Gorgonian corals (Rumphella ag-gregata) form bushy colonies with long slender branches.
