Why Female Naked-Mole Rats and Meerkat Bones Grow Longer During Pregnancy

In the last month, I wrote the stunning post which suggested that a chemical that is associated with human reproduction might be the key to remodel and realign the human skeletal structure. Now, I show evidence that the phenomena of a female who is going through pregnancy is much more common that most people would believe.

So far, there has been two other vertebrates that researchers have studied and seen bone growth during pregnancy. They are the naked-mole rate and the meerkat. Tyler once asked me to look over the study on pregnancy of naked-mole rats and I decided to go back on those studies to look them over.

It seems that the reason these smaller mammal rodent-like creatures goes through body size increases is because they were kept from going through puberty.

As we might know, not all animal species has the same type of social structure as ours. When it comes to the naked-mole rats, they are what is known as eu-social.

There is just 1 female in an entire colony which can have babies, and somehow they can control the other females in the colony from ever going through puberty. It might be due to a certain chemical released or a completely social aspect. As the article states… “In most other mammals, puberty begins with the release of GnRH and activation of the hpg axis (Terasawa and Fernandez, 2001)”

The increases in the length of the lumbar spine region happens when the former subordinate females who could not go through puberty and become reproductively active is removed from the groups that they are in. Whatever was controlling them is removed.

The researchers not only removed the subordinate female out of the group, but also put them in a cage alone with a male, which caused in a few weeks vaginal perforation.

The result, even before the onset of pregnancy is that the female who is not no longer suppressed ends up much bigger in weight and length (by 82% and 37%, respectively).

Not only that, during pregnancy, the female also increases in length. If is only after she has given birth, and had not enough time to have pregnant again yet does the increase in lumbar length stop.

The researchers have now used this phenomena in the study to show that even the smaller, mammals seem to go through a phase similar to what we humans go through in puberty.

When we looked at the same type of phenomena happening the meerkat species, (Article: Adaptive Size Modification by Dominant Female Meerkats), we found that the bigger females and males were always the dominant one in the group, and would block reproductive chances by the other members of the group of the same sex. Only the most dominant and largest of the ones would mate and have litters.

When the researchers measured the levels of the hormones…

• Luteinizing Hormone (LH)
• Estradiol
• Cortisol

…In the females, they found that these hormones were raised in the dominant members.

The same was true when they looked at all the male members in the group and compared the…

• Testosterone
• Cortisol

….levels in the male and found the dominant one to have a higher level of the hormone.

I refer to three studies, “Cessation of Reproduction-Related Spine Elongation After Multiple Breeding Cycles in Female Naked Mole-Rats” and “Skeletal mass, chemistry, and growth during and after multiple reproductive cycles in the rat. Bone. [PubMed]” and “Growth and factors affecting body size in naked mole-rats.”

From the 1st study, the reason for the increase bone size is due to… “In other mammals (such as rats and humans), pregnancy-induced bone growth occurs to prepare the skeleton for the demands of lactation–a time of rapid bone depletion….While we did not measure bone loss in this study, it is possible that bone mineral resorption was occurring in naked mole-rats during the lactation period.“

It seems the the Meerkat subordinates suffer from the same type of endocrinology effect as what is seen in the subordinates in Naked-Mole Rats.

They lack both the circulating sex hormones & mature glands. This means that which they have all the right tools in their bodies, they are not triggered, until you give them a chance to be free from the suppression from the larger members of their groups.

This shows that the phenomena that we see in the smaller mammals is NOT another case of females pregnancy induced bone growth, but more of a puberty-like phase.

It seems that estrogen and progesterone, the chemical we already know effects human females during pregnancy, is also elevated in this rodent-like mammals during their pregnancy. However, that doesn’t help us much in our endeavor. Both of the hormones do contribute in bone formation and remodeling, but in us humans, almost all of us past a certain age have already gone through with puberty. There is a big difference in the reproductive patterns between humans and naked-mole rats and meerkats.

Click Here for more information and see the radiology pictures on how much a small subordinate female can change her body when she is allowed to grow and reproduce.