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Easter: Egg Eaters

Pumilio on handIt seems a long time ago since I showed my beautiful daughter her first wild Strawberry Poison-dart Frog in Costa Rica. It’s always a wonderful experience seeing such jewels in the wild and at the moment Adam my assistant is traveling through Panama and Costa Rica, where he too is coming across many strawberry poison- dart frogs.

This species varies greatly in colour throughout its range; frogs from differing localities may be red, green, blue, yellow or a combination of these colours and with varying patterns.  However, whatever their colours and wherever the area they inhabit, the one thing that never changes is the strawberry dart frog’s call, which is an insect like sound. Males are extremely active and call throughout the day to declare their territories and also attract females.

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Newly hatched tadpole being carried on back of parent frog through public exhibit at Manchester Museum (c) Adam Bland

Once a female has chosen a male she produces a small clutch of 1-6 eggs on a leaf or on the ground, which are then fertilised. The frog guards the eggs for about 10 days until ready to hatch. Upon hatching the tadpoles are then very carefully transported on the back of the parent to the water-filled centres of a bromeliad plant. Here they are deposited  then carefully cared for – when hungry, the female frog comes back to lay infertile eggs within the bromeliad which the tadpoles will then feed upon. They eat nothing else but these ‘food’ eggs. This is where the frog species gets its Latin name from, ‘Oophaga’ meaning ‘Egg Eater’, which directly refers to the tadpole’s very specialised diet.

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Metamorphosing tadpole of strawberry dart frog on public display at Manchester Museum (c) Andrew Gray

The aquatic nursery chosen for the developing tadpoles is like a miniature pond formed by rainwater being funnelled down the outer leaves into the heart of the plant, and is prevented from evaporating by the dense shade of the leaves. The tadpole takes about 50 days to metamorphose into a perfect, half-sized strawberry dart frog.


Strawberry dart frog exhibit, The Vivarium, Manchester Museum (c) Andrew Gray

As you may know, we have a large centrepiece exhibit at the museum that features this particular species. Over the past few weeks many of our visitors have been lucky enough to witness them breeding naturally in the exhibit, including being able to see the tadpoles being carried on the backs of the adults as well as swimming in the bromeliads and emerging as newly formed froglets. If you haven’t seen our Strawberry dart display then please come along to take a look – you won’t be in bad company.        

Watch another video featuring Strawberry dart frogs in the wild Here. 

Urban Naturalists


Smooth newt (c) Matt Wilson

On Saturday (29 March), Rick Parker, chairman of Bolton Conservation Volunteers, will be running a workshop at the museum as part of our Urban Naturalist series. Urban Naturalist is a series of friendly, practical workshops run by leading naturalists. If you would like to find out more about amphibians and other animals which live in ponds, their needs and requirements, and how you can develop an attractive pondlife environment for these animals why not join Rick here this Saturday between 2-4pm. Rick has been Chairman of Bolton Conservation Volunteers for over 30 years, a group that manages habitats for wildlife and in particular ponds and their surroundings to encourage newts and rare dragonflies. To book a place please call 0161 275 2648.

Build your own pond – Froglife: Just Add Water

Vivarium App Development

At the moment Adam and I are working on providing information to support a superb new project which is currently underway here called ‘Mapping the Museum’. It aims to enhance collections through the use of Augmented Reality (AR) and 3D mapping visualisation. The first phase of the project is focusing on amphibian and reptile species found in the Vivarium and there will be 2 new applications developed. The first will be called ‘Virtual Vivarium’ – Developed using Google Earth the Virtual Vivarium is the app any visitor will be able use to find out more about the amphibians that are currently both on display and behind the scenes. The Virtual Vivarium will provide exciting new content on:

  • Where in the world all the amphibian species in the vivarium are located – it visualises the most up-to-date distribution maps from the International Union for Conservation of Nature (IUCN) and our expertise here using the 3D Google Earth globe.
  • Detailed species descriptions including photographs, videos and relevant links.
  • All the in-situ costa rican conservation work we are involved in.
  • Issues surrounding the threats amphibians are facing, using a case study of Madagascar which shows how their habitat has changed over time due to deforestation using satellite image animation

virtual_vivarium copy

Fabulous Frogs App: Splendid & Native Developed using Junaio the Fabulous Frogs App: Splendid and Native is an interactive Augmented Reality (AR) tool which is targeted at 7 – 11 years (Key Stage 2) incorporating the following learning objectives and features based around the Splendid Leaf Frog:

  • Where the Splendid Leaf Frog lives in relation to the learner
  • Understanding the anatomy of frogs (see below).
  • Frog life cycle – comparison between the Splendid Leaf Frog and the native Common Frog, including quick quiz questions for each stage of the life cycle
  • Viewing our Splendid Leaf Frogs with David Attenborough
  • In-depth  exploration of related Frogblogmanchester content
  • How you can help – Sponsor a Frog

vivariummockup_anatomy copy

Both these 2 exciting new apps are planned for release this summer and will be accessed exclusively through taking a photo of a Splendid Leaf Frog on Frog Blog Manchester with your phone or iPad.

  Mapping the Museum – SCARLET

Teaching taxonomy

photo[3]practicalToday I delivered a practical teaching session based on adaptation and classification for our 1st year Zoology and Biology students from the Faculty of Life Sciences. The session allowed the students a first-hand experience with a wide range of unusual animals from the Vivarium and introduced them to basic taxonomy and the use of dichotomous keys.

I would like to say a big thank you to all the demonstrators who helped today and also what a pleasure it was to welcome our students from FLS to the Museum – I hope they enjoyed the session as much as I did delivering it!

Costa Rican frog call study

Whilst on the University of Manchester field course in Costa Rica I conducted a project on frog calls, surveying the main swamp area that receives heavy rainfall almost all year round. I focused on the acoustic activity of the Red-eyed Leaf Frog, Agalychnis callidryas. In this post I present the most important conclusions from this study, as well as some interesting notes on the acoustic behavior of other pond breeding frogs.

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Study Site at La Selva (c) W.Chaves

One accurate way to interpret behavior in pond breeders is to analyze their acoustic activity along a shared area. My main focus was tracking the calling activity of male A. callidryas throughout the night, but the study also allowed me to identify 5 other species that might influence the species’ presence in certain areas of the pond.

After 3 nights of sampling, I concluded that the calling activity of A. callidryas was strongly diminished by the calls of the Hourglass Tree Frog, Dendropsophus ebraccatus, which is a little bit smaller than A. callidryas (Males about 23-27mm). This species was also the most widely distributed species along the study area, in contrast to others, such as Scinax eleaochroa, which presented a particularly high calling activity during the first night (it reduced for the remaining 2 nights).


Hourglass Tree Frog, Dendropsophus ebraccatus (c) W.Chaves

The other three species (Tlalocohyla loquax, D. phlebodes, and A. saltator) presented a shy calling activity. However, the weather conditions could have influenced this as A. saltator is reported to be more active and even breed ‘en mass’ during heavy rainfalls. As for T. loquax and D. phlebodes, their low calling activity suggested no influence over the calls of the A. callidryas.

Since D. ebraccatus was the only species which proved to be affecting the calling activity of A. callidryas, I then decided to look more closely into this particular interspecific behaviour. While the A. callidryas males called in order to attract females to their higher perches, D. ebraccatus were usually found lower down, near shallow water where sedges or semiaquatic plants dominated. Although males of A. callidryas were also seen calling from low perches, there were few if any suitable leaves for this species to lay its egg masses on there. The calling of A. callidryas from low perches may also have been affected by neighbouring frogs at this level as these would cause a high level of acoustic interference.

 Almost at midnight, the calls of A. callidryas diminished along with the calling activity of all other hylid species found at the swamp. This group response could be interpreted as an anti-predatory strategy to decrease the risk of predation from bats. However, to hear the frog calls I was working with here is a sound recording I made that includes the species mentioned:  

Male Red-eyed Tree Frog, Agalychnis callidryas, at the study site. (c) W. Chaves

Conducting projects that investigate specific animal behaviours, such as the one which focuses on the calling activity of A. callidryas, are of growing importance. When considering future studies on the ecology, bio-acoustics, and the different aspects of reproduction in this species, an extension of this project’s methodology may be useful. I intend to develop it in future assessments of populations of this species along its Atlantic distribution.

I hope to share some more information on frogs of the Neotropics in further posts, but would like to encourage visitors to comment on my work  –  or if you have any suggestions or ideas for the project`s improvement or other future science projects please post a comment, I would love to hear from you. Many thanks, Wagner.