Teddy Bears and Hamsters: A 1900s Pet Scam

Still on the European Hamster (Cricetus cricetus), I came across this story in The Zoo Story by L.R. Brightwell, a history of London Zoo published in 1952.


Leonard Robert Brightwell (1889-1962) was a well-known and prolific author and illustrator. He had strong zoological connexions since he illustrated The Science of Life for the authors, H.G. Wells, Julian Huxley and G.P. Wells.

In his chapter covering the decade 1901-1910 and under the heading of one of his drawings showing how Fellows of the Zoological Society were dressed at the time while looking at a far more intelligent Chimpanzee, he wrote on the appearance of a new toy:

     …A matter of unscientific interest also was the arrival from U.S.A. of that still popular nursery potentate, the Teddy Bear…It is now generally agreed that the toy was really inspired by the Koala, or Billy Blue Gum, an Australian marsupial. But we are all full of Teddy Roosevelt, his famous range of dentures, fire-eating speeches and highly coloured hunting adventures. Whatever the nursery favourite's real origin, it is from the irrepressible "he-man" president that it took its name. The toy's immediate and tumultuous popularity led to a strange development in the animal trade. Certain livestock dealers—with a shrewd eye for what the public evidently wanted—gave it the "Teddy Bear Rat". This was the hamster, a chubby, handsomely marked beast not unlike a guinea pig and so abundant in some parts of the Continent as to be a plague. This is the rodent said to have eaten the cruel bishop in the Rhenish “Mouse Tower". To launch such a dirt-cheap creature on the public at an extravagant figure seemed to the business mind elementary common sense. But the hamster unfortunately combines with the guinea pig's chisel teeth a very unguinea-pig-like temperament. It led to so many complaints and damaged fingers that the police eventually prohibited its sale. The Zoo soon had to refuse offers of Teddy bear rats, so eager were disgruntled householders to part with their spiteful pets.

European Hamster at Vienna Central Cemetery in 2009
By katanski and used by Wikipedia

The European Hamster has always had a terrible reputation for biting its keepers in captivity and for defending itself in the wild. George Jennison in his Natural History Animals of 1927 wrote:

     It is an irascible creature, a bold and determined fighter with its own kind and against vultures and smaller birds, dogs, cats and the lesser carnivores that prey upon it.

The UFAW Handbook 6th edition says European hamsters are capable of inflicting serious bites but that at the Hannover medical school they have been tamed by frequent handling and personal attention to individuals such that ‘a large degree of tameness can be achieved in successive generations’. That is also true of the other hamsters kept as pets and in labs, the Syrian, Chinese and Djungarian but the European is that much bigger and a braver (wo)man than me would be needed to start the process.

Chapter heading from Brightwell's book

Updated 9 November 2019

European Hamsters and Maize Fields. A Nutritional Route to Local Extinction?

I have not seen a European Hamster (Cricetus cricetus) in the wild despite having twice looked for them at dusk in a hedgerow in Hungary where they had previously been seen—a classic case of, ‘if only you had been here last week’.

European Hamster photographed at Vienna Central Cemetery
by katanski (image used by Wikipedia)

Observations of the hamster in the wild have indicated they feed on cereal crops, tubers and invertebrates. Hamsters hoard large amounts of food in their burrows and they hibernate. There is evidence that after hibernation female hamsters do not emerge from their burrows before their first pregnancy of the season, relying until then on their hoarded seeds. During gestation and lactation they emerge and supplement their diet of seeds with fresh plants like clover and invertebrates such as earthworms.

Using females from a captive colony of European Hamsters, the group first studied the effect of four different diets after emergence from hibernation: wheat+clover; wheat+earthworms; maize+clover; maize+earthworms. Similar numbers of young were born with all four diets. However, there was a marked difference in their early survival. On the wheat+earthworm diet, 80% of young survived to weaning while on the other three diets survival to weaning was under 12%. Clearly, something was missing from the diet; protein at about 18% of the diet one would guess with the clover supplement (compared with over 40% with earthworms). However, there was a clear difference between wheat and maize in terms of survival of the young.

At this point, human nutritionists would be bouncing up and down to tell you that there is a key difference between wheat and maize: the content and bioavailability of niacin (Vitamin B₃ or nicotinamide) are much lower in maize and that, given the supply of earthworms rich in other nutrients that are relatively low in maize, the most likely nutrient lacking would be niacin.

The next season, a simple experiment was done. The maize+earthworm diet was compared with the same to which niacin was added. The results were clear. From a mean of less than two surviving until weaning with the maize+earthworm diet, supplementation with niacin increased that survival to over four.

The authors continued:

…regarding the European hamster, given that wild populations of this species are surrounded by 55–80% of intensively managed maize monoculture in Alsace (France), with sized field of 1.4 ha that corresponds to seven times the home range of a female, extremely low crop rotations (i.e. sometimes more than seven successive years of maize cultivated in the same plot) and high use of herbicides—dramatically reducing the proportion of adventive species—wild hamsters are undoubtedly constrained in their diet.

Now, you may ask, having demonstrated that nutritional deficiency can affect the survival of young hamsters to weaning, do the authors have any evidence that is a key cause of the decline of the species in France? In other words, do observations in the wild show the number of young emerging from the burrow, particularly from the first litter of the season, to be low?

The discursive paper (some of the data presented are irrelevant to the main story) which could have benefitted from a benignly dictatorial editor, raises several other questions. For example, nowhere I can see is any comparison made with data from the captive colony fed a presumably ‘complete’ diet. What was the litter size, survival to weaning etc. compared with the best performing experimental groups?

I must admit to being confused on the ‘normal’ litter size at birth of the European Hamster which is why a comparison with the breeding colony would have been informative. I have found value of 4-18 young, with numbers declining since about 1980³. I have also found an account that there is a strong genetic element determining litter size in captive colonies⁴.

The reduction in litter size after parturition seemed to vary from a gradual loss on the wheat+clover diet, for example, to a complete lack of lack of maternal care in most of the animals on maize+clover. It is well known that if nutrition is inadequate or other environmental conditions are not right, female rodents kill and eat their young thereby conserving their resources to try again when the chances of producing fit young are better. Indeed a great deal of effort in he past went into devising diets for laboratory rodents, including hamsters, of course, to overcome such problems. So to those of us who have kept rodents the lack of maternal care in the malnourished hamsters was to be expected. However, true to form that British comic which masquerades as a newspaper, the Daily Mail, was on form when it picked up this story:

There is evidence in Syrian Hamsters that the sex ratio is manipulated after parturition by maternal cannibalism in different environmental conditions⁵. Having some proprietorial interest in mechanisms controlling the sex ratio in rodents, in my case the selective reabsorption of embryos in the Guinea Pig⁶, it would be of interest to know the sex ratio of the young surviving to weaning in the different experimental groups.

Again back in the real world, how many animals could be affected by niacin-deficiency from eating cultivated maize as a staple in the wild, Tissier et al. wondered. American Black Bears with young, as opposed to bears without young, avoid eating maize and other cultivated crops. They also suggested that bees could be adversely affected by feeding too heavily on maize pollen.

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Updated 9 November 2019

1 Tissier ML, Handrich Y, Dallongeville O, Robin J-P, Habold C. 2017 Diets derived from maize monoculture cause maternal infanticides in the endangered European hamster due to a vitamin B3 deficiency. Proc. R. Soc. B 284, 20162168. http://dx.doi.org/10.1098/rspb.2016.2168

2 Tissier ML, Handrich Y, Dallongeville O, Robin J-P, Weitten M, Pevet P, Kourkgy C, Habold C. 2016. How maize monoculture and increasing winter rainfall have brought the hibernating European hamster to the verge of extinction. Scientific Reports 6 25531 doi: 10.1038/srep25531

3 Surov A, Banaszek A, Bogomolov P, Feoktistova N, Monecke S. 2016. Dramatic global decrease in the range and the reproduction rate of European hamsters Cricetus cricetus. Endangered Species Research 31, 119-145 doi 10.3354/esr00749

4 La Haye MJJ, Koelwijn HP, Siepel H, Verwimp N, Windig JJ. 2012. Genetic rescue and the increase of litter size in the recovery breeding program of the common hamster (Cricetus cricetus) in the Netherlands. Relatedness, inbreeding and heritability of litter size in a breeding program of an endangered rodent. Hereditas 149, 207-216

5 Beer AK, Zucker I. 2012. Sex ratio adjustment by sex-specific maternal cannibalism in hamsters. Physiology & Behavior 107, 271-276 doi: 10.1016/jphysbeh.2012.09.001

6 Peaker M, Taylor, E. 1996. Sex ratio and litter size in the guineapig. Journal of Reproduction and Fertility 108, 63-67