Cuban Crocodiles and our outlook on the conservation of species:

George Hancock

Crocodylus rhombifer:

Size: Up to 10 to 12 ft.

Appearance: Enlarged teeth and post orbital horns, coppery colouration with black speckling, reduced webbing on feet and elongated limbs.

Diet: Changes throughout development from small invertebrates to large mammals.

Behaviour: Unusually terrestrial and aggressive. Some evidence of pack hunting.

Reference: http://apps.webofknowledge.com/full_record.do?product=UA&search_mode=GeneralSearch&qid=5&SID=N1cqp92sibcO88zG8wR&page=1&doc=1

Historic Range:

• The lowest distribution of any modern crocodile• Population of less then 3,000 individuals last recorded in 1996

Reference: http://www.jstor.org/stable/1437061?seq=2#page_scan_tab_contents http://www.iucnredlist.org/details/5670/0

The great overharvest:• During the 1970’s there was a mass over harvesting

of crocodilians for the leather

• The worse effected species with the best patterning and the least ossification of their scales

• This overharvest was enabled by the availability of spotlights and sturdy boats

• Reducing the risk and difficulty of crocodile hunting

Farming

Reference: Biology and evolution of crocodilians by Gordon Grigg and David Kirshner

Current Circumstances:

Risks

Reference: http://www.iucnredlist.org/details/5670/0

1. Poaching

2. Habitat Loss

3. Loss of Ancestral prey

4. Introduction of Caiman to the isle of youth

5. Hybridization

1) Poaching:

Reference: http://www.fws.gov/international/permits/by-species/alligator-and-crocodiles.html

• Illegal hunting has increased substantially since the 1990’s

• This is primarily for the tourist industry selling meat to private restaurants

• This remains an issue despite the presence of 2 crocodile farms on the island

• Legal hunting requires special permits and then licensing for the trade of meat and leather

2) Habitat loss:

Reference: http://onlinelibrary.wiley.com/doi/10.1111/cbi.2002.16.issue-4/issuetoc

• Cuba like many of the poorer regions of the developing world struggles with issues such as illegal logging

• However irrigation has lead to an increase in the salinity of the Zapata swamp due to irrigation to the coast putting fresh water species at risk

• The Cuban Crocodiles low distribution also makes them vulnerable to development around their surrounding habitat

• However thanks to effective management schemes Cuba has seen a 31.8% increase in forest cover since 1990 (655,000 Ha)

3) Loss of ancestral prey:

Reference: Phenomena.nationalgeographic.com/2015/04/29/you-just-missed-the-last-ground-sloths/

• Ground sloths once inhabited the islands of the Caribbean until they went extinct 4,200 years ago

• It has been hypothesized that the Cuban Crocodiles more terrestrial and social nature, was to enable them to hunt the large ground sloths

• This could be linked to the decline of the Cuban Crocodiles distribution and population as we lack population estimates prior to the overharvest

• However the extinction of the sloths correlates with human arrival in the Caribbean 1,200 years before hand

Megalocnus (The Great Sloths)

4) Introduction of Caiman:

Reference: http://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=222

• When trade in baby American alligators became illegal the spectacled caiman was imported in the thousands as a substitute

• They have since become a major pest species with their small size allowing them to survive off of smaller amounts of food and having a rapid reproductive rate (40 eggs per nest)

Caiman crocodilus (Spectacled Caiman)

5) Hybridization:

Reference: http://www.ncbi.nlm.nih.gov/pubmed/25335559http://onlinelibrary.wiley.com/doi/10.1002/jez.471/abstract

• 2014 study by the university of Havana found 49.1% of Cuban Crocodiles to have significant hybridisation using samples of mitochondrial DNA

• Crocodiles captive at local farms were found to have 16.1% of individuals be hybrids

• However a previous study in 2011 found the American Crocodiles surrounding Cuba to be more closely related to the Cuban Crocodile then to other American Crocodile populations

• This extensive hybridisation was found by comparing ten polymorphic microsatellite loci in addition to mitochondrial markers.

Questions Raised:• How can we find a balance between ecotourism and habitat disruption?

• How should the public treat the farming of high trophic level organisms?

• Should we conserve species that are going extinct for non human reasons?

• Should we only conserve species which fall within the evolutionary species definition?

• Do you think that the Cuban Crocodile should be conserved?