Habits and Habitats

Habitats and Behaviours

Hi again!

We were going to conduct an audit in Benny’s backyard to see how many toads and frogs currently inhabit it, but unfortunately, our research has informed us that most toads and frogs are quite inactive in winter. Instead, we have done some internet research about the habitat requirements and behaviour patterns of frogs and toads.

Cane toads:

• Prefer open clearings in urban environments, grassland and woodland
• Do not have specific breeding requirements – they just need a body of fresh water (or even up to 15% salinity) of almost any nature
• Tend to prefer pools of water that have shallow, muddy slopes without too much vegetation
• Enjoy well-manicured lawns
• Are mostly active in the evenings in warm months of the year
• During the day, like to keep cool under rocks and in hollow logs

We did a bit of general research about native frogs, and some more specific about two breeds that are known to inhabit the Brisbane area:

• Green tree frogs are typically found in the canopy of trees near a still-water source. However, they can survive in swamps (among the reeds) or in grasslands in cooler climates.
• The Striped Burrowing Frog (C. alboguttata) lives in woodlands, grassy and cleared areas. It is usually only seen around temporary pools and water-filled claypans. The species is active by day and night
• Different species of native frogs have different habitat requirements. For example, some tree-dwelling frogs shelter on the underside of leaves while others burrow into sand or hide under rocks
• There are several breeds of native plants that would be suited to a habitat of native frogs, for example, swamp lily, marsh flower and water snowflake would be suitable to plant in ponds, while native ginger, bird’s nest fern and mat rushes would suit the sides of the pond

Sources:

Moreton Bay Regional Council

http://www.moretonbay.qld.gov.au/uploadedFiles/moretonbay/environment/fauna/Frogs.pdf

Australian Museum

http://australianmuseum.net.au/Green-Tree-Frog

Frogs Australia Network

http://www.frogsaustralia.net.au/frogs/display.cfm?frog_id=117

Toads have in-built Earthquake Warning system

...And another really interesting document from the Australian Geographic website, http://www.australiangeographic.com.au/, from March 31st, 2010.

TOADS ARE CAPABLE OF detecting an impending earthquake several days before the first tremors strike, and alter their behaviour accordingly, a new study suggests.

"Our study is one of the first to document animal behaviour before, during and after an earthquake," says Rachel Grant, lead author of the study at the Open University in England. "Our findings suggest that toads are able to detect pre-seismic cues such as the release of gases and charged particles, and use these as a form of earthquake early warning system."
Though anecdotal reports and previous studies of ants, rats and birds have shown animals altering behaviour in advance of an earthquake, this is usually just hours before the event and near to the epicentre. The toads in this study were shown to react, even though they were many tens of kilometres away.

Dramatic change
To make the discovery, Rachel led researchers who studied a population of common toads at a breeding site located 74 km from the epicentre of the major earthquake that struck L'Aquila, Italy, in April 2009. Comparing data collected before, during and after the event, they found that the toads displayed a dramatic change in behaviour five days before the earthquake.
According to the study, published this week in the Journal of Zoology, the amphibians abandoned spawning and left breeding sites, not resuming normal behaviour until several days after the event.
The change in behaviour coincided with disruptions in the uppermost electromagnetic layer of the Earth's atmosphere, say the authors - thought to be caused by the release of radon gas or gravity waves prior to the earthquake. The researchers speculate that the toads sensed and responded to these early warning signs of the coming quake.

Escape strategy
Rachel and her co-workers argue that since toads move slowly there is evolutionary pressure for them to develop an effective early escape response strategy.
Biologist and toad expert Rick Shine, at the University of Sydney, says that the finding has intriguing implications.
"I don't doubt that many kinds of wild animals have ways of detecting things that science has yet to unravel," he told Australian Geographic. "It certainly sounds as if the Italian toads are better at forecasting an earthquake than we are, and it would be fascinating to learn more about the subtle cues that apparently enable them to do so."

(source: http://www.australiangeographic.com.au/journal/toads-have-inbuilt-earthquake-early-warning-system.htm)

This is a photo of a 'frog flood' that occurred 2 days prior to the devastating earthquake in the Sichuan province of China, May 2008. The officials wrote it off as normal behaviour, but we know better.

Who's Eating Who?

This week we have been conducting some research around what cane toads eat in a suburban Brisbane environment. It turns out that they can eat almost anything that fits into their mouths. No wonder they are so successful at adapting to the Australian environment. We have organised the information that we have found into a partial food web, just showing the predators and prey of the cane toad.

We then did some investigating into the predators and prey of the green tree frog, or Litoria caerulea, to see how much competition is between them. It looks like they have very similar dietary requirements.

Now we have to think about how we can use this information to inform our habitat design.

Information Sources:
Australian Museum - Cane Toads
Queensland Government – Cane Toads Information

Australian Museum

The Cycles of Life

One of the issues that we need to research is how native frogs and toads differ at points throughout the life cycle, as identifying the differences between frogs and toads is crucial for creating a native frog friendly habitat. There are lots of different native frog species and they are all slightly different. One important tip that we learnt is that cane toadpoles are always black, while native tadpoles are never purely black. Annie practiced some observational drawing as she was learning about the differences between the cane toad and the green tree frog. What differences can you see?

Cane toad life cycle

Green tree frog life cycle

Predators

There are very few predators of the cane toad in Australia, hence their prolific growth in numbers and spread across the country.
There have been some instances of animals biting back, as it were...

Snake attempting to devour a toad

A freshwater crocodile giving it a go...

A king brown snake not knowing what's good for it...

A quoll finishing off its toad meal...

But just when you think there is some hope, one of the best predators of the toad is the Keelback snake, and it seems this toad wants revenge...

Cane toad making a meal of a Keelback snake!

Can you identify the parts of a frog?

In order to classify frogs and toads, we must refer to certain external features or characteristics. Many of these are the same for both frogs and toads.
Can you identify the following parts on the frog picture to the left?








I've made it a little easier and already identified them for you.
1. cranial crests
2. parotid gland
3. tarsus (shank)
4. dorsolateral folds
5. femoral area (thigh)
6. toes with digital discs
7. toes without digital discs
8. tympanum

Identifying cane toad eggs/toadlets

What to do with cane toads near your frog pond

• Cane toads are a risk to mature frogs and their tadpoles
• Remove cane toad eggs from your frog pond, or they will poison the water in your frog pond and the ‘toadpoles’ will eat your ‘tadpoles’
• It’s easy to identify toad eggs, they are the only ones laid in long clear strands like spagetti. The eggs look like a row of little black dots. Destroy the cane toad eggs by taking them out of the water and leaving them to dry

This is what cane toad eggs look like. Make sure to take them out of your frog pond if you see them! They are really easy to pick up in your hands

• Toad tadpoles tend to be smaller than frog tadpoles and are usually found in dense swarms. Toadpoles are pure black, native frog tadpoles have light-coloured undersides.

Example of toadpoles.

• Whether or not you have a frog pond, it’s a good idea to collect adult cane toads at night and freeze them in a plastic bag. Beware the poison glands on their backs. Another humane method for killing cane toads (there is no reason to be cruel — they didn’t ask to come here) is to squirt them with Dettol or Toadex — but not salt.
• The bodies of the dead cane toads can be composted.

In the news: New species of frog discovered

Asia's tiniest frog has just been discovered on the island of Borneo. When fully grown, it is no bigger than a pea! Read more on the article here
I wonder if there are any other frog species yet to be discovered in Australia? What do you think? If there are, where might they be hiding?

The Biggest??

This is a photo of the biggest toad I could find! Can you beat it?

See a video at:

http://www.youtube.com/watch?v=s_onANXeIPA

Or what about this one?

Life cycle of frogs and toads

Here is a small animation we made in our Science tutorial, just brushing up on our iMovie skills. The students will make an animation of their own, charting the life cycle of toads and frogs

Frogs of Brisbane and how to identify them: Is it a frog or is it a toad?

Did you know that there are 49 frogs listed as occurring in the regions surrounding Brisbane?
Have you ever seen frogs or toads in your garden at home? Some are really easy to identify as frogs, but there are a lot of dark brown native frogs in Brisbane that someone might mistakingly attempt to hurt thinking it is a cane toad.
The experts at the Amphibian Research Centre have posted some pictures here of all of the frogs found in Brisbane, also listing the identifying features of them all. Just click on the pictures for more detailed information.
This is a really useful tool to have access to when conducting your backyard survey.
Below in blue is what Amphibian Research Centre have posted about identifying a cane toad in your back garden. (Some of the terms you might need to look into a little further, such as finding out what where the glands and tubercules are located on a frog)

Visible features
Presented here is the information stored in the frogs.org.au database which is used to identify frogs based on their appearance. It is intended to be used in a key guide for separating species so some of the information (for example, back colours) may be rather non-specific. The system is currently being developed - if you notice errors in the data, please write to Dave Black at the address at the bottom of the page.
Important note: This information details only the appearance of the frog. If an "or" appears in the description, this may mean either that there is some variation within the species or that the feature might be observed differently by different people. For example, if a frog has very small toe pads, it may be listed as having "Toe pads: present or absent"

Size
Up to greater than 90mm

Eyes, hands, and feet
Pupils: horizontal
Toe pads: absent
Webbing on feet: half-webbing or full-webbing

Belly
Texture: smooth
Pattern: plain
Colour: multi-coloured with only black, grey, and white or multi-coloured featuring a colour in addition to black, grey, and white

Back
Texture: rough or warty or ridged
Pattern: plain or mixed / marbled
Colour: single colour or multi-coloured

Glands and tubercles
Parotoid gland: present
Tibial gland: absent
Metatarsal tubercles: Non-keratinised glands present (fleshy or uncoloured)