History and origin
The Yellow-bellied toad was first described by Linnaeus in 1758, the scientific name of this species is Bombina variegata. Bombina from Latin meaning 'hum' from their call. Variegata also comes from Latin and means 'varied', 'different', 'irregular' because of their irregular patterns on their belly.
Characteristics
They are characterised by their amazingly bright yellow bellies, looked at closer you can see just how cute these toads are because their pupils are in the shape of a heart.
Description =Size=
- Eggs: The eggs measure about 1.5 to 2 mm in diameter.
- Tadpoles: The tadpoles measure 7 to 9 mm long when they exit the egg. Older tadpoles reach around about 55 mm long.
- Juveniles: The juveniles measure 12 to 16 mm long when they exit the water.
- Adults: Adults measure up to 56 mm long, although averaging 40 mm long (males are smaller then females growing to max. 45 mm long). =Morphology=
- Eggs: They are laid in separate balls, they are round and laid on twigs, up to 170 eggs are laid in small groups (of about up to 30).
- Tadpoles: Their tail is less then 1.5 times the length of the body. They have a tall tail that comes up slightly onto the back.
- Adults: They have a flattened appearance, their back is very warty and they have many small openings on the warts on the back and all over the belly and legs, there is usually a small black point at the tip of this. From these openings the toad can excrete a white liquid which it uses for defence. Their snout is rounded. Their hind feet webbing is almost total. They lack paratoid glands and have a heart shaped pupil. They lack a vocal sac. =Patterns & colours=
- Eggs: They are greyish or creamy on top. Light brown to white on the underside.
- Tadpoles: Darker on top, usually brown. Tail lighter with small dark patches.
- Adults: Their back is light brown sometimes with darker blotches of brown (usually on a large area of warts). They get their name from their unique belly colour and pattern, it is yellow with dark brown or dark gray (sometimes even dark blue) spots and blotches linked sometimes (the distribution of yellow/darker areas is an identification key for specimens within a population).
Geographical range Found over much of central Europe and in much of the Balkan peninsula. In the 2 northern thirds of France, excluding the north east area (Pas-de-Calais; Lille) and the and much of the west too (Nantes and southern ares until La Rochelle). Introduced into the UK.
Subspecies - scabra - Found in Montenegro, Albania, Greece, Bulgaria and Romania. B.v.Kolombatovic is sometimes considered a sub-species in Dalmatian animals, this is due to hybridisation with Bombina bombina. Otherwise they are part of B.v.scabra. - variegata - Found Found in central Europe, France, Switzerland, Germany...
Sexual differences
The males have a dark nuptial pad which is slightly visible, however in the breeding season this feature is at it's most obvious.
Seasonal variations
Males have dark nuptial pads on the inside of their front legs which is very visible, they also have these pads on 3 of their inner fingers of the front legs. During the aquatic phase, the pattern on the belly becomes lighter.
Diet
They feed on: 1/3 beetles the rest is composed of ants, spiders and other insects.
Defensive habits
If threatened of feel cornered on ground they do what is known as Unkenreflex, they lift their head and limbs, showing their yellow underbelly after a few seconds they try to flee (this is more common in cool temperatures) they may also excrete a white liquid from the small openings of their body. Males may release a distress call. If in the water, they just try to flee to a safer place under the water.
Reproduction
The breeding season starts at the beginning of April there may be up to 3 mating sprees ending in August, these breeding sprees are triggered by rainfall. The mating happens when the water temperature is superior to 11 C. The egg laying usually happens at night. The male sings to attract a female. When he spots a female the mating begins. The male grabs the female by the hips, slowly they move over to a vegetated area in the water where on their arrival the female gets hold of a twig of a piece of vegetation, she then tickles the males hind feet with hers, this excites the male and after a short moment of this the male squeezes the female harder as if they were cuddling. The female then ejects some eggs which the male fertilizes (around 5 to 10 eggs are released). The female then turns around the twig or branch which she was holding onto in order to attach the eggs to it, after this happens, the male and female move to another suitable plant and between 5 to 10 minutes later the second lot of eggs is released by the female. A female may lay up to 150 eggs each breeding period. The embryo develops in 2 to 3 days. Metamorphoses occurs between 1 to 4 months.
Sexual maturity, life span
The average life span for Bombina variegata is about 9 to 10 years, they reach their sexual maturity in their second year.
Habits
Active by day and also although less, at night. They are very aquatic and sociable, with many specimens found together in a small area of water. They are very active and lively toad who are often seen floating with legs spread out on the water surface. They often come onto land to hunt, this happens mostly after rain. Their young can be found up to a kilometre away from water. They are usually found when overturning rocks, stones and logs, they hibernate on land. If they are disturbed whilst in water, they will dive to the bottom of the mud (if there is any, maybe in ponds...).
Call
The call is a musical like, 'uuh...uuh...uuh' these sounds are regular. The sound is almost like the chimes of a clock on the hour. The single sound can be repeated up to 40 times in a minute. They don't have a vocal sac, which explains why this species has a short call which is repeated many times, sound (p)www.oreilleverte.com:
Habitat
Found living under 1200 meters in altitude. Their preferred habitat is open, sunny, shallow water holes often with little vegetation (ponds, pools, marshes, woods, shallows at edges of rivers, streams...). Their terrestrial habitat is usually woods, open and not too dry areas with wood.
Predators
The eggs and tadpoles are in danger from water insects and the larva of the Fire Salamander (Salamandra salamandra) and of newts. Adults are often hunted by birds.
Found over much of central Europe and in much of the Balkan peninsula. In the 2 northern thirds of France, excluding the north east area (Pas-de-Calais; Lille) and the and much of the west too (Nantes and southern ares until La Rochelle). Introduced into the UK.
Image showing a Yellow-bellied toad, Bombina variegata performing Unkenreflex - © Daniel Phillips
