Bruce Lyon brought this short video to my attention. How does a nocturnal mammal get about with her young?
The video asks why they do this? Well, it’s clear that it keeps the family together, and here’s one explanation:
Shrews are highly territorial animals and only socialise with one another in the mating season. Females have three or four litters of 5-7 young between May and September. Females are promiscuous and a litter may have two or three different fathers. Young shrews are occasionally observed following their mother in a ‘caravan’. Each shrew grasps the base of the tail of the preceding shrew so that the mother runs along with a line of young trailing behind. This behaviour is often associated with disturbance of the nest and may also be used to encourage the young to explore their environment.
How much exploring can you do when your nose is up your sister’s butt? Can you think of any other reasons?
Here’s a daytime conga:
If you can’t get a baby sitter?
Mom needs a Carmen Miranda-style be-fruited headdress.
It might help them become familiar with their immediate surroundings near their current nest. But I don’t know what it’s like to be a shrew.
On a perpendicular note, parents can receive a fair amount of ridicule or hostility if they dare put a tether on a small child while out shopping in a busy place. But why is that? Actually, it seems pretty sensible.
Sixty years ago I had two precious little boys just over one and two years old – who were ‘runners’. Turn your head and at least one of the little buggers was tearing down an isle or heading in the opposite direction. I weighted ~100 lbs and a 25+ lb child was too heavy for me to carry around. When out, if the stroller was not available to contain them, I used harnesses. Although it would have been nice to train them to behave like the shrews do. Many other people used harnesses at the time. It worked well, kept little ones safe, and I don’t understand what the problem is today. Anyway, I suppose there are many ideas today where the logic escapes me.
I think acceptance of this is different for some countries.
I had to wear a harness when my parents took me to the store when I was very young, as I was active and would run off. I can still remember the shame of being dragged along ON A LEASH!
Very cute.
It must be a blind mammal thing – baby moles do something similar, but instead of holding on they use their sense of smell – to follow the aroma of molasses. Tish Boom! – I’m here all week, folks…
By way of atonement, here are the “RSPCA’s weirdest animal rescues of 2021 – in pictures”: https://www.theguardian.com/artanddesign/gallery/2021/dec/30/rspcas-weirdest-animal-rescues-of-2021-in-pictures
I think that in the first video, the shrews are Suncus etruscus, the etruscan shrew, one of the smaller species of mammals, weighting less than 2 grammes (a species of bat is smaller if I remember well). In the National Geographic video, it is apparently Crocidura russula, the greater white toothed shrew. This behavior is common in several species of the Crocidurine shrews (white toothed shrews), and is mostly used when the nest is disturbed or menaced: the mother knows her territory very well, including several “rest places” which can be used as replacement nests. If the mother would have to carry the youngs one by one to a new, secure place, she should make the trip 6 to 8 times, what’s extremely dangerous. Of course, the conga behavior cannot be used before the youngs are developped enough, but the energy already invested in a younger litter is also less important – yes, it is a dry heartless economic reasoning, but so is the nature.
Thanks for the suggested species identifications!
Also, thanks for the other bits of info & speculation.
It was also very interesting to read of the mother’s promiscuity in the NG video.
Does anyone know if this alleged promiscuity is operating with shrews in general?
Or just that species?
Would that complex behavior be an example of the adaptive value of “disguised paternity”?
That is my own term — but I would love to know if it has any currency in zoology.
To wit — Does a mother gain advantage for her offspring if the males of a community all somehow “know” that any offspring of a certain female might be their own?
The promiscuity was demonstrated in the other subfamily of shrews, the Soricines (shrews with red teeth) and particularly in Sorex araneus, a very individualistic species. The winter territories are strictly individual and don’t overlap each other. During the reproductive season, the females keep or even increase their winter territories, but he males are more wandering around. It was suggested that multiple paternity (up to 6 different fathers in the same litter!) is an insurance against inbreeding.
Other species, and particularly Crocidurine, are more tolerant socially, but I don’t know about multiple paternity.
I should add here that Jacques is a biologist who studies shrews, so he knows whereof he speaks.