Life History and Reproduction


       When the first skeleton of the Good Mother Whale was found, it was determined right away to be female. It had an intact fetal skeleton within it which had characteristics of many sexual reproducing mammals today. It was stated in an article that the newborn of Maiacetus inuus was commonly related to the newborn of fallow deer (Gingerich et al. 2009). The newborn of Maiacetus inuus was also said to be similar to the fallow deer because it was more developed in the womb. This is so that it would be born more mature in order to be able to feed itself almost right after development. This makes them similar to all the marine animals today whose young are also developed in the womb for early feeding independence.

         There is a clear sexual dimorphism between the Maiacetus inuus in multiple studies (Gingerich et al. 2009; Perkins 2009). There was also another Maiacetus inuus found and it was inferred to be a male because there was no skeletal fetus and its skeletal structure was much larger than that of the female (Gingerich et al. 2009). It also had common skeletal characteristics of a male (Gingerich et al. 2009) and it is also assumed that males did not fight for the attention of a female mate but spread out among each other through the sea.     

     One of the things about the female skeleton of Maiacetus inuus that helped scientists gather the most information on the reproduction of this organism was that there was an intact skeletal fetus within the skeleton. The position of the fetal skeleton says a lot about the reproduction and young of Maiacetus inuus. The fetal skeleton was in a head-first birthing position which, in large-bodied land mammals, is a universal posture for birthing (Gingerich et al. 2009). This is not normal for marine mammals that are fully aquatic. The discovery of this lead to the explanation that semiaquatic protocetids still gave birth on land (Gingerich et al. 2009).

       Also, because the skeleton still had the fetus within it, it gave scientists enough information to figure out that Maiacetus inuus also gave birth on land. This is why they had hind limb-like structures. This allows a newborn to breath during labor (Gingerich et al. 2009). Later generations of the whale show that they slowly lost the hind limbs to support birth on land and thus started aquatic birthing.

Continue on to Interactions to continue learning about Maiacetus inuus.