African Giant Pouched Rats, Cricetomys gambianus, are native to sub-Sahara Africa but a small population in Florida is potentially an invasive species. I briefly introduce the problems invasive species like this one can cause in the United States.

1. African Giant Pouched Rats as
invasive species
Danielle N. Lee
Department of Zoology
Oklahoma State University

2. Problem with invasive species
• Disrupt local ecology
– Overconsumes local resources
– Displaces and/or eliminates locals in similar
guild/ecological niche
– Introduces new diseases, parasites
• New Human-Wildlife conflicts
– Agriculture pests
– Zoonoses

3. Native habitat of African Pouched Rats
This is the field where I found and trapped Cricetomys summer 2012 in Morogoro, Tanzania.
This habitat is very similar to that of Southern Florida where Cricetomys have been found by
the Florida Fish & Wildlife Authorities

4. Wider view of the field site I used to trap and track African Pouched Rats, Summer 2012.
Notice the open field in the foreground and the mixed woodlands in the back ground. Just
behind this thin strip of trees was a small ravine or river.

5. My most successful trap,
along the edge of the habitat
of the open field and dense
trees near a ravine (river).
Just under the thick of trees is
the burrow I discovered when
releasing animals from the
traps.
The rats seemed to prefer
dense habitats that provided
cover.
I only captured animals in the
cover or along the edge, never
in the open field.

6. A burrow I discovered while trapping and tracking Cricetomys Summer 2012.

7. Close up of the burrows created and used by African Pouched Rats. These are the burrows
of rats in an outside enclosure.

8. Peterson et al. (2006)
created a model predicting
distribution of African
Pouched rats if they were to
able to establish a
population in the United
States.
Given that ecological niche
influences geographical
potential and ecological
behavior of a species can be
invariant to community
context, these invasive
distribution models predict
that the rats would obey the
same ecological rules if they
were in a novel setting
(Peterson et al. 2006).
Florida and the Southern
United States would be ideal
habitat for my rats.

10. African Pouched rats are very large, but reports of their size has been exaggerated. Adult
rats range in size of 1 – 1.4 kg and 67-74 cm long – that includes the tail. (Perry et al.
2006). The largest rat I handled this summer was 1.7 kg and 80 cm long.

11. They are also long-lived rodents, up to 7 years in captivity. Fecundity is reported to be high (
up to 30 pups a year). However, my preliminary research indicates we know too little about
the reproductive biology of this species to say that.

12. African Pouched Rats as Agriculture
Pests
Palm nuts and corn kernels from
the cheek pouch of a rat I was
handling Summer 2012.
Star fruit from the orchard along the
trapping line I used to capture, mark
and recapture rats Summer 2012.

13. As agriculture pests, rodents cause an estimated annual lost of 5-15% of corn which is ~$45
million in crop and food loss in Tanzania alone (Stenseth et al. 2003).

14. I use bananas as bait for my trapping efforts, but citrus and other tropical fruits are local
crops which are vulnerable to rodents. Florida, which has a similar ecology and orchard-
agriculture industry could be devastated if the rats were to increase their numbers and
extend their distribution.

17. African Pouched Rats as Zoonosis
• Infectious diseases that can be spread
between species
• Great public health concern for diseases that
can be transmitted from animal to humans
• Monkeypox
• Lassa Fever
• Leptospirosis

18. Key References
Native-range ecology and invasive potential of Cricetomys in North America.
AT Peterson, M Papes, MG Reynolds, ND Perry, B Hanson, RL Regnery, CL Hutson, B
Muizniek, IK Damon, DS Carroll. 2006. J Mammalogy, 87(3):427-432
Rapid assessement for a new invasive species threat: the case of the Gambian giant
pouched rat in Florida. R Engeman, JW Wollard, ND Perry, G Witmer, S Hardin, L
Brashears, H Smith, B Muiznieks, B Constantin. 2006. Wildlife Research, 33:439-448
Monkeypox zoonotic associations: insights from laboratory evaluation of animals
associated with the multi-state US outbreak. CL Hutson, KN Lee, J Abel, DS Carroll, JM
Montgomery, A Olson, Y Li, W Davidson, C Hughes, M Dillon, P Spurlock, JJ
Kazmierczak, C Austin, L Miser, FE, Sorhage, J Howell, JP Davis, MG Rynolds, Z Braden,
KL Karen, IK Damon, RL Regnery. 2007. Am J Trop Med Hyg, 76(4): 757-767
New Invasive Species in Southern Florida: Gambian rat (Cricetomys gambianus). ND
Perry, B Hanson, W Hobgood, RL Lopez, CR Okraska, K Karen, IK Damon, DS Carroll.
2006. J Mammalogy, 87(2)262-264
Mice, rats, and people: the bioeconomics of agriculture rodent pests. NC Stenseth, H
Leirs, A Skonhoft, SA Davis, RP Pech, HP Andreassen, GR Singleton, M Lima, RS
Machang’u, RH Makundi, Z Zhang, PR Bron, D Shi, X Wan. 2003. Front Ecol Environ, (7):
367-375