Development of fetal characteristics and estimation of implantation date in the spotted seal, <i>Phoca largha</i>

DOI Web Site
  • Sasaki Risa
    Faculty of Bioindustry, Tokyo University of Agriculture
  • Sakurai Yuta
    Graduate School of Bioindustry, Tokyo University of Agriculture
  • Kobayashi Mari
    Faculty of Bioindustry, Tokyo University of Agriculture NPO Marine Wildlife Center of JAPAN

Bibliographic Information

Other Title
  • ゴマフアザラシ（<i>Phoca largha</i>）の胎仔成長における形質の発現と着床日の推定
  • ゴマフアザラシ(Phoca largha)の胎仔成長における形質の発現と着床日の推定
  • ゴマフアザラシ(Phoca largha)ノ タイシセイチョウ ニ オケル ケイシツ ノ ハツゲン ト チャクショウビ ノ スイテイ

Search this article

Abstract

This study investigated the development of characteristics during the growth of Phoca largha fetuses. Delayed implantation is known to occur in seals, but there are very few reports investigating the date of implantation. This study estimated the date of implantation and examined the significance of delayed implantation. Dates of deaths of fetuses were converted into sequential day numbers (day 1 = January 1). The whiskers, nails and hairs of fetuses were observed from day 250, 262 and 358, respectively. Early whisker and nails development were followed by the development of hair and was consistent with results reported for other seals. Teething was observed on the same day that hairs were observed. The finding that hair and teeth are developed and eyes open by the time of birth was consistent with precocity. Moreover, analysis of allometric growth based on body length and the measurement of other parts revealed characteristics of tachy-auxesis in many parts of the body. In particular, flippers showed a higher allometric coefficient, possibly because P. largha pups start swimming soon after weaning. The average date of implantation was estimated to be August 7th and the 95% confidence interval was July 23rd to August 15th.

Journal

Keywords

Details 詳細情報について

Report a problem

Back to top