Tooth extraction is however an invasive procedure and whilst useful in necropsy examinations, in live animals, alternative less invasive methodologies are being investigated. The most standardized methodology involves counting tooth growth layer groups (GLGs) in medial longitudinal sections of teeth. Establishing chronological age in cetaceans has proved challenging, due to minimal external signs of aging, with several methodologies currently utilized. Determining the age of stranded individuals with limited pathology on post mortem examination can provide a reliable insight into the cause of death. There are no patents, products in development or marketed products to declare.Įstimating the age of cetaceans can have large implications in interpreting scientific data of individual health assessments, reproductive status and population demographics. This does not alter our adherence to PLOS ONE policies on sharing data and materials. Partial funding for this study was also received from the Gulf of Mexico Research Institute Grant Number GOMRI2015-V-186.Ĭompeting interests: The authors have read the journal's policy and the authors of this manuscript have the following competing interests: TS is a paid employee of Seaworld. The specific roles of these authors are articulated in the ‘author contributions’ section. SeaWorld did not have any additional role in the study design, decision to publish, or preparation of the manuscript. SeaWorld provided the radiographic equipment used to take the radiographs of the dolphins at SeaWorld as well as the salaries of veterinary technicians and trainers involved in the logistics of obtaining the radiographs. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.ĭata Availability: All relevant data are within the manuscript and its Supporting Information files.įunding: Seaworld provided support this study in the form of salaries for TS. Received: JAccepted: SeptemPublished: September 26, 2019Ĭopyright: © 2019 Barratclough et al.
PLoS ONE 14(9):Įditor: Stephen Raverty, Animal Health Centre, CANADA In conclusion, knowledge of the lifespan and the onset of sexual maturity for each species will allow this model to be applied to other cetaceans, facilitating age estimation via pectoral radiography in future research.Ĭitation: Barratclough A, Sanz-Requena R, Marti-Bonmati L, Schmitt TL, Jensen E, García-Párraga D (2019) Radiographic assessment of pectoral flipper bone maturation in bottlenose dolphins ( Tursiops truncatus), as a novel technique to accurately estimate chronological age. This diagnostic tool could also be applied to diagnose atypical ossification patterns consistent with nutritional, developmental or growth abnormalities, and identifying subclinical health issues. Managed care dolphin ages could be properly estimated with decreasing precision from within 3 months in animals 30 years old. Completion of epiphyseal closure of the long bones correlated with average sexual maturity. Third order polynomial regression calculated separate age predictor formulas for male and female dolphins, with females reaching sexual maturity earlier than males. The most informative areas to evaluate morphologically were the metaphyseal regions of the radius and ulna, and the proximal and distal epiphysis of metacarpals II and III. A numerical score from -1 to 8 was assigned to 16 anatomic locations on the pectoral radiograph, to create a formula to estimate age. A database of 126 radiographs from 94 dolphins of known chronological age was utilized to establish the stages of skeletal ossification over time. Establishing a non-invasive method of accurately aging bottlenose dolphins across the entire age range is important to long term conservation efforts to understand health status, lifespan, reproduction and survivability. These methods are inaccurate in dolphins > 13 years old, due to overlapping of the growth layer groups in dolphins and worn teeth. The most frequently utilized methods to age bottlenose dolphins ( Tursiops truncatus) include tooth extraction counting dental growth layer groups and dental radiography. Accurate age estimation in wildlife conservation is an important diagnostic tool in the interpretation of biological data, necropsy examination, reproductive status and population demographics.
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