The Cane (Bufo) Toad in Florida

Dr. Steve A. Johnson—tadpole@ufl.edu

Dept. of Wildlife Ecology and Conservation

Presentation Overview

• Brief overview—introduced herps• Established amphibians• Cane Toad in FL

– Background– Identification– Distribution– Ecology– Impacts– Management– Resources

Introduced Herps in Florida

• Amphibians: ~15 species documented– 4 salamander species– 13 frog species4 species currently established and breeding

• Cuban Treefrog, Greenhouse Frog, Cane Toad, Clawed Frog• Coqui previously established, single ind. heard calling 2017

• Reptiles: ~160 species documented – 4 crocodilian species– 29 turtle species– 41 snake species– 89 lizard species59 species currently established and breeding!

• 1 croc, 5 turtles, 5 snakes, 48 lizards

Data from Krysko et al., 2016. IRCF Reptiles & Amphibians 23:110-143

FL’s Introduced Amphibians

• Established Frogs:– African Clawed Frog (breeding, eradication efforts underway)

• Native to sub-Saharan Africa, first observed in 1970’s?,

isolated population near Tampa, aquaculture/pet industry

– Greenhouse Frog (breeding)

• Native to Cuba & Bahamas, first observed in FL in 1863, likely

a stowaway in cargo, breeding in much of state

– Cuban Treefrog (breeding)

• Native to Cuba, Bahamas & Cayman Islands; first observed in

1920’s; likely a stowaway in cargo; breeding in most of

peninsula

– Cane Toad (breeding)

• See following slides

Cane Toad Background

• Aka: Bufo, Giant, Marine Toad

• Native to Central & South America

• Introduced numerous places around the world

• Major pest in Australia

• Declines of native species—toxicity

• Multiple introductions in FL 1930s-50s:

biological control, pet escapes

• Found in central and southern peninsula

• Expanding range in SW Florida

Cane Toad Identification

• Family Bufonidae—Squat body, short legs,

warty skin, poison glands

• Brownish back with mottling, sometimes darker,

sometime yellowish

• Very enlarged parotoid glands, triangular

shaped

• May exceed 3 in., up to 6 in., metamorphs

small (size of raisins)

• Ridge around eyes and above nose

• No cranial crests

Cane Toad Identification

Brownish back,

often with mottling

Enlarged parotoid

glands, triangular

May exceed 3 in.,

up to 6 in.

Ridge around eyes

and above nose

No cranial crests

Cane Toad IdentificationMetamorphs small

(size of raisins)

Extremely difficult to

distinguish from native

Southern Toad

Sexually dimorphic

Females more light spots

Males rougher skin

Cane Toads

Native Southern Toad

vs. Invasive Cane Toad

Cane Toad Distribution

Swath across state—Tampa

to Miami/Keys

Isolated population in

Deland

Expanding in SW FL

Gaps may be lack of

documentation

Cane Toad Ecology

Found in suburban and ag. settings (human-

modified)

Rarely invade large, intact natural areas

Ground-dwelling, do not climb well

Breed in ditches, canals, lakes, retention

ponds; call is melodious drumming

Eggs laid in strings

Feed on diversity of insects, small verts.,

pet food

Impacts of Cane Toads—

EcologicalEcological impacts probably minor

Do not invade large natural areas in Florida

Most commonly encountered in residential and agricultural settings—suburban yards, golf courses, fields

Predators of native species—insects & small vertebrates

Potential impacts on native Southern Toads???

Toxicity impacts to native FL wildlife appear negligible

Impacts of Cane Toads—

Human Quality of Life & $$$

Potentially lethal to pets, mainly dogs

Cost of treatment $$$

Maybe toxic to koi fish—all life-stages are toxic

Presently, Cane Toads in Florida

are more of a socio-economic

issue than an ecological problem.

Cane Toad Management

Turn off outside lights, replace with “bug lights”

Remove pet food and water bowls

Remove eggs laid in ornamental ponds

Remove debris piles and hiding places in yards

Do not leave pets unattended, esp. at dusk and night

Capture and euthanize Cane Toads—be sure ID is correct!

Hand capture adults (“Toad Busting”)

Dip net and trap tadpoles

Contact nuisance wildlife trapper

Cane Toad ManagementEuthanizing Cane Toads—Be sure of ID

Anesthetize (benzocaine, lidocaine) then freeze (AVMA approved)

Chill then freeze (Shine et al. 2015)

Wash your hands after handling toads

Cuban Treefrog Example

Resources• My website http://ufwildlife.ifas.ufl.edu/

• “The Cane or Bufo Toad (Rhinella marina) in

Florida” http://edis.ifas.ufl.edu/uw432

• Video series in preparation: background,

identification, euthanasia—stay tuned

• Southwest Florida CISMA

https://www.floridainvasives.org/Southwest/

• EDDMapS for reporting Cane Toads

https://www.eddmaps.org/

• Please email me too: tadpole@ufl.edu

Help Needed

• Dr. Ben Muller—UF Post doc

– May to November 2018

– Trap and call lure development

– Developing outreach package

– Collaborating with FWC

• Looking for volunteers for ~June-Sept.

Email Dr. Steve Johnson tadpole@ufl.edu