Effect of enrichment and cage size on
growth in young rehabilitated
hedgehogs (Erinaceus europaeus)
Vervaecke, Hilde
De Vriendt, Kathleen
Laevens, Hans
Agro- & Biotechnology, Ethology and Animal Welfare, KAHO Sint-Lieven, Hospitaalstraat 23, 9001 Sint-Niklaas, Belgium
INTRODUCTION
Hedgehog rehabilitation
Hedgehogs are difficult to raise successfully in some rehabilitation centers,
with high sudden mortality and bad growth, even when the animals feed
well. This may relate to multiple factors, one of which may be the stressful
captive environment. Enrichment and larger cage size are generally expected to enhance welfare if it allows the animals to perform strongly motivated behavioral needs such as locomotion and exploration.
Rehabilitation center
Hypothesis
It can be assumed that animals whose basic biological needs are fulfilled,
will show lower stress and will grow better than animals in restrictive environments. We examined the growth of the animals in small versus large,
combined with enriched versus poor conditions.
Individual 2
Individual 3
Total number of
animals per year
Brasschaat
3100
Number of
hedgehogs per
year
80
Hand raised
hedgehogs
Opglabbeek
7018
816
275
Oostende
3075
130
20
Merelbeke
4000
300
20
Herenthout
2500
122
38
40
MATERIAL AND METHODS
Study animals
We studied 8 young hedgehogs, 4 males, 4 females, weighing between 500
and 800 grams. The hedgehogs were kept in the VOC Brasschaat. They had
been hand-raised coming in from the wild in a weakened state or were
captive-born to rehabilitated mothers.
Latin Square design (repeated for each sexe)
Individual 1
Data on numbers of animals were obtained by a written enquiry
(data apply to 2010).
Individual 4
PERIOD 1
Large
Enriched
Large
Not enriched
Small
Enriched
Small
Not enriched
PERIOD 2
Large
Not enriched
Large
Enriched
Small
Not enriched
Small
Enriched
PERIOD 3
Small
Enriched
Small
Not enriched
Large
Enriched
Large
Not enriched
PERIOD 4
Small
Not enriched
Small
Enriched
Large
Not enriched
Large
Enriched
Latin square
The experiment followed a Latin square study design to examine the effect
of size (small i.e. 60x60x60 cm versus large i.e.120x60x60 cm) and enrichment (enriched versus poor).
Experimental period: during four periods of 13 days each, the hedgehogs
were kept in different experimental conditions. All the animals changed four
times to another cage: to a large cage with or without enrichment or a small
cage with and without enrichment. There were thus four different experimental periods to take into account. The entire period covered 52 days
(from August till October 2011).
Habituation period: Prior to the start of each “experimental period” the
hedgehogs stayed in the experimental cage for 6 days to habituate to the
novel environment.
Small (60x60x6) enriched cage Small non enriched cage
Weighing
In the experimental period, the hedgehogs were weighed every three days.
Statistical analyses
Analyses were performed with a SAS 9.2 Proc MIXED model, taking into account the starting weight. The effect of cage size and cage enrichment (four
classes), period (1 to 4), and of individual (1 to 4) on average weight gain
was analyzed for males and females separately.
(Large=120x60x60 cm)
RESULTS
RESULTS
What was the effect of cage size and cage enrichment, period and of individual on average weight gain?
Average weight gain
Males
For the males, we found no significant effects. They grew roughly equally
well in all cages and periods for all individuals.
NS
* P<0.05
Females
Large
Large
Small
Non Enriched
Enriched
Non Enriched
Small
Enriched
Large
Large
Small
Small
Non Enriched
Enriched
Non Enriched
Enriched
For the females, we found a significant effect of treatment (P<0.05), period
(P=0.03) and individual (P=0.03) on weight gain. On average they gained
more weight in larger cages and in enriched cages. They grew best in the
large enriched cages.
CONCLUSION
Do males have less problems with environmental stressors?
It is possible that males may have a lower sensitivity to environmental stressors than females. Whereas females grew poorly in poor and small environments, for males this did not make a difference. In the wild males have larger home ranges and exhibit more risk-taking behavior. They prefer larger gardens and more open areas. They move about 3 km per night whereas females move three times less. The hypothesis of larger female sensitivity to poor
environments should be further examined.
Acknowledgements
We are gratefull to the Vogelopvangcentrum Brasschaat for their kind cooperation. The other wild animal shelters kindly shared relevant information.
Benelux Congress of Zoology, Brussels, 2012