Hug me, squeeze me! Amplexus.

Mating frogs in swimmingpool in Argentina
Mating frogs in swimming pool in Argentina

Amplexus is a Latin word meaning embrace. The male frog clasps the female in a tight embrace; some literally glue themselves onto their partner. I’m sticking with you babe!

 

The embrace itself varies: some males grab their partner round the waist; others hold their lady frogs under their armpits; and some – like the passionate poison dart frogs – place the backs of their hands against their lovers throats!

Mating frogs in swimming pool in Argentina
Mating frogs in swimming pool in Argentina

It’s all about hanging on to her until she lays her eggs, which he can then fertilise as soon as they are released. It’s the best place to be if you want to be the daddy!

 

There’s a wonderful series of illustrations showing all of the weird positions of amplexus in different species of frogs on this website created by the University of Michigan (1).

  1. http://animaldiversity.org/collections/contributors/Grzimek_herps/Anura_diagrams/v06_id64_con_amplecti/

 

A small frog with a big voice!

Sapgreen Stream Frog (Hylarana nigrovittata)
Sapgreen Stream Frog (Hylarana nigrovittata)

I came across this small pond frog whilst staying in northern Thailand recently.  They were inhabiting water filled lily-pots outside my bedroom at a charming resort called Malee’s Nature Lovers Bungalows, Doi Chiang Dao (1).  They made quite a lot of noise, but it was a nice noise and quickly lulled me to sleep!  Before going to bed, I went outside and tried to photograph them.  They slipped quietly into the water when I approached them with a flash-light, but with patience, I managed to get close enough to some of them and get some half-decent pictures with my pocket camera.

Sapgreen Stream Frog (Hylarana nigrovittata)  showing markings on leg and body
Sapgreen Stream Frog (Hylarana nigrovittata) showing markings on leg and body

It took me a while surfing the Internet before I managed to identify it as the sapgreen stream frog (Rana nigrovittata).  At least I think it is!  This species also goes by the name of the Black-striped frog, but these individuals shown here do not have a prominent stripe. This species is however, a ‘species complex’ of more than one species and with at least three distinct morphs (2). In other words, there is still a lot to find out about this frog. There is a picture of some not very stripy Black-striped frogs on this EcologyAsia website (3) and on another website called Reptiles and Amphibians of Bangkok (4). I also came across some published research work which had found that frogs of this species lived for up to nine years (5).  That’s quite a long lifetime for such a small animal; perhaps it takes a long time to learn how to croak well!

Sapgreen Stream Frog (Hylarana nigrovittata)
Sapgreen Stream Frog (Hylarana nigrovittata)

Thankfully it is not considered threatened and is listed as being of Least Concern ‘in view of its wide distribution’ which extends from southern China down into the northern half of Peninsular Malaysia (2).  I forgot to record the ‘song’ (vocalisation) on my camera, so dear reader you will just have to image what a loud noise can emanate from one so small!

Sapgreen Stream Frog (Hylarana nigrovittata)
Sapgreen Stream Frog (Hylarana nigrovittata)

1) http://www.maleenature.com/ 2) http://www.iucnredlist.org/details/58681/0 3) http://www.ecologyasia.com/verts/amphibians/black-striped_frog.htm 4) https://bangkokherps.wordpress.com/frogs/sapgreen-stream-frog/ 5)  Khonsue, Wichase, Masafumi Matsui, and Yasuchika Misawa. “Age determination by skeletochronology of Rana nigrovittata, a frog from tropical forest of Thailand.” Zoological Science 17.2 (2000): 253-257.

A malee of mating frogs

Marsh frog (Rana ridibunda) floating on a pond surface
Perez’s frog floating on a pond surface

 

Marsh frog (Rana ridibunda) mating
Perez’s frog (Pelpphylax perezi) mating

Whilst I was waiting for a flight back to London at the small airport at La Coruna, in northwest Spain, I went for a walk outside the terminal building and found a pond full of mating frogs! It was a nice way to spend the time waiting for my flight and I was able to watch and photograph the frogs in the Spring sunshine. Spring was certainly in the air for these frogs, which are Perez’s frog, also known as Iberian waterfrog, Iberian green frog, or Coruna frog (Pelophylax perezi) (1) and they were croaking away and hurling themselves at each other with abandon!

Marsh frog (Rana ridibunda) leaping
Perez’s frogs leaping

This was presumably their mating ritual, although most of the leaps ended in one frog colliding into another, or missing it completely as the other frog swiftly moved out of the way! Perhaps they were just frisky! I am not sure if any of them were actually mating, they mostly seemed to be leaping about and croaking. Perhaps this was party time! I think what was happening was that this pool contained a high density of males all calling and tussling with each other to try to attract a female to come and mate with them. There were quite a few frogs basking in the sunshine around the edge of the pond; or at least they were until I approached, and they leapt into the safety of the water with a satisfying plop!  Perhaps these were the admiring females? Although this one looks fairly nonplussed!

Marsh frog (Rana ridibunda) sitting by the edge of the pool
Perez’s frog sitting by the edge of the pool

Some individuals seemed a lot more relaxed than others, perhaps they were just having a break from the proceedings, and floated serenely on the surface of the pond.

Marsh frog (Rana ridibunda) floating or resting
Perez’s floating or resting

This species is found in southern France and across the whole of the Iberian Peninsula. It has been introduced to the Balearic Islands, and the Canary Islands (Spain), as well as two sites in the United Kingdom (Kent and Surrey) (2).

One of the most striking features of this frog are they two inflatable vocal sacs either side of the head. These little greyish balloons are inflated very rapidly and can be sucked back in very quickly as well.

Marsh frogs (Rana ridibunda) mating
Perez’s frogs mating
Marsh frogs (Rana ridibunda) fighting? With vocal sacs enlarged
Perez’s frogs fighting? With vocal sacs enlarged

For photographers, I took these images at a shutter speed of 1/1000th second which unfortunately, was not fast enough for some of the shots. A speed of at least 1/2000th second would probably be needed to ‘freeze’ the leaping frogs.

Marsh frog (Rana ridibunda) leaping out of the pond
Perez’s frog leaping out of the pond
  1. http://amphibiaweb.org/species/5124
  2. http://www.iucnredlist.org/details/58692/0