A wild Indo-Pacific bottlenose dolphin adopts a socially and genetically distant neonate

Alloparental behaviour and adoption have been reported in many mammals and birds. Such behaviours are energetically costly, and their causes and functions remain unclear. We observed the adoption behaviour of a wild Indo-Pacific bottlenose dolphin (Tursiops aduncus) near Mikura Island, Japan. A calf was seen with its mother on six observation days. Following the mothers death, the calf was observed with a sub-adult female on all 18 observation days from May to September 2012. On three days, the calf was observed swimming with this female in the suckling position and milk was seen leaking from the females mammary slit. A five-year dataset revealed no significant social or kin relationships between the biological mother and allomother, indicating that kinship and social relationships did not play an important role in the observed adoption

Data from: Non-invasive age estimation based on fecal DNA using methylation-sensitive high-resolution melting for Indo-Pacific bottlenose dolphins

<p class="MsoNormal"><span>Age is necessary information for the study of life history of wild animals. A general method to estimate the age of odontocetes is counting dental growth layer groups (GLGs). However, this method is highly invasive as it requires the capture and handling of individuals to collect their teeth.</span><span> Recently, the development of DNA-based age </span><span>estimation methods has been actively studied as an alternative to such invasive methods, of which many have used biopsy samples. However, if DNA-based age estimation can be developed from fecal samples, age estimation can be performed without touching or disrupting individuals, thus establishing an entirely non-invasive method. </span><span>We developed an age estimation model using the methylation rate of two gene regions, <em>GRIA2</em> and <em>CDKN2A,</em> measured through methylation-sensitive high-resolution melting (MS-HRM) from fecal samples of wild Indo-Pacific bottlenose dolphins (<em>Tursiops aduncus</em>). The age of individuals was known through conducting longitudinal individual identification surveys underwater. Methylation rates were quantified from 36 samples. Both gene regions showed a significant correlation between age and methylation rate. The age estimation model was constructed based on the methylation rates of both genes which achieved sufficient accuracy (after LOOCV: MAE = 5.08, <em>R<sup>2</sup></em> = 0.34) for the ecological studies of the Indo-Pacific bottlenose dolphins, with a lifespan of 40-50 years. This is the first study to report the use of non-invasive fecal samples to estimate the age of marine mammals.</span></p><p>Funding provided by: Japan Society for the Promotion of Science<br>Crossref Funder Registry ID: https://ror.org/00hhkn466<br>Award Number: 17K19426</p><p>Funding provided by: Japan Society for the Promotion of Science<br>Crossref Funder Registry ID: https://ror.org/00hhkn466<br>Award Number: 21K05726</p><p>Funding provided by: Japan Society for the Promotion of Science<br>Crossref Funder Registry ID: https://ror.org/00hhkn466<br>Award Number: 21K12331</p><p>Funding provided by: Japan Society for the Promotion of Science<br>Crossref Funder Registry ID: https://ror.org/00hhkn466<br>Award Number: 22J12473</p><p>Funding provided by: Tokai University General Research Organization*<br>Crossref Funder Registry ID: <br>Award Number: </p><p>Funding provided by: Tokai University Supporters Association Research*<br>Crossref Funder Registry ID: <br>Award Number: </p&gt

Spontaneous Ejaculation in a Wild Indo-Pacific Bottlenose Dolphin (<i>Tursiops aduncus</i>)

<div><p>Spontaneous ejaculation, which is defined as the release of seminal fluids without apparent sexual stimulation, has been documented in boreoeutherian mammals. Here we report spontaneous ejaculation in a wild Indo-Pacific bottlenose dolphin (<i>Tursiops aduncus</i>), and present a video of this rare behavior. This is the first report of spontaneous ejaculation by an aquatic mammal, and the first video of this behavior in animals to be published in a scientific journal.</p></div

Spontaneous ejaculation by a wild Indo-Pacific bottlenose dolphin off Mikura Island, Japan.

<p>(A) Dense seminal fluid was ejaculated from the tip of the penis with initial contraction of the peduncle muscle downward. (B) A few seconds after the first ejaculation of seminal fluid, the remaining seminal fluid was ejaculated for 0.86 s (26 frames at (1/30 s)/frame).</p