Toads are interesting creatures that live part of their lives on land and part in water. These amphibians are great swimmers and typically migrate to ponds during the breeding season. But can toads drown?
Despite their ability to breathe underwater through their skin, toads can drown. The oxygen they absorb while underwater is usually not enough to meet all their oxygen needs for a long time, so they can only stay submerged for a limited time before they have to surface to breathe air with their lungs.
For example, if a toad is entangled in a net, its oxygen stores will deplete rapidly and the toad may drown if it is unable to reach the surface.
Toad Tadpoles Can Not Drown (Usually)
Most toads start their lives as tiny tadpoles. Tadpoles are very different from adult toads because they’re adapted for a fully aquatic life (life in the water), while adult toads are adapted for a mostly terrestrial life.
Toad tadpoles have gills on either side of their head, and a flat paddle-like tail fin to help them move in the water.
At this stage, toad tadpoles breathe underwater through their gills, just like fish.
Their gills have an extensive capillary network very close to the skin surface; Oxygen that is dissolved in the water that comes in contact with their gills is absorbed into their bloodstream via diffusion.
At the same time, carbon dioxide from the bloodstream passes through the gills and is diffused into the water. This gaseous exchange allows them to stay underwater almost indefinitely.
However, sometimes toads lay eggs in water with low levels of dissolved oxygen – and when the tadpoles hatch, so they cannot get all the oxygen they need by absorbing it from the water.
If tadpoles are in water with a low oxygen content and no way of getting any extra oxygen, they can drown.
For this reason, most tadpole species also develop lungs in addition to their gills. To breathe air with their lungs, tadpoles need to break through the water’s surface to get a gulp of air.
How Tadpoles Breathe Air
When they first hatch, the tadpoles are too feeble to break through the water’s surface. To get around this, they “bubble-suck”.
To do this, they first stick their open mouths to the underside of the water’s surface. They then open their jaws wide and suck at the water’s surface. Doing this creates an air pocket that they can pinch off by quickly closing their jaws.
After they close their mouth, a portion of the fresh air bubble is forced down into their lungs. The excess air is then burped out as a small bubble that floats back up to the water’s surface.
Once the tadpoles get bigger, they will be strong enough to break through the water’s surface for a gulp of air.
Adult Toads Can Drown
After a few weeks months, to a few months (depending on the species), the tadpoles will go through a process known as metamorphosis and transform into adults.
During this process, they will lose their gills, and tails, and develop limbs for walking on land.
Once fully transformed, tiny toads typically less than an inch long will leave the water and live on land. These tiny frogs will grow into adults and once they mature, they will go back to the water to breed and lay their eggs.
Adult toads have well-developed lungs which they use to breathe air. They take air through their nostrils, and down into their lungs.
Apart from breathing using their lungs, frogs also can breathe through their skin and thin membranes in their mouth and throat to get extra oxygen.
The oxygen that comes in contact with their skin and membranes is absorbed into the bloodstream via diffusion.
At the same time, carbon dioxide from the bloodstream passes through the skin and membranes and is diffused into the atmosphere.
This process of “skin breathing” is known as cutaneous respiration (sometimes informally called “skin breathing”).
How Toads Breathe Underwater
When underwater toads can breathe using their lungs, instead, they breathe underwater by absorbing oxygen that comes in contact with their skin.
Dissolved oxygen in the water that comes in contact with this skin is absorbed into the bloodstream via diffusion. At the same time, carbon dioxide from the bloodstream passes through the skin and is diffused into the water.
However, this method of breathing does not give most toads all the oxygen they need, so they can only be underwater for a limited time before they have to resurface for a gulp of air.
Prolonged stays underwater can lead to suffocation and drowning.
How Long Can a Toad Stay Submerged Before Drowning?
How long a toad can stay underwater before drowning is mainly dependent on 4 factors, namely: how much dissolved oxygen there is in the water, the temperature, the toad species, and how active the toad is.
Depending on these factors, most toads can stay underwater from a few minutes to several hours at a time.
1. How Much Dissolved Oxygen Is in the Water
Toads can stay submerged in water with a high oxygen content for much longer than they can in water with a low oxygen content. The oxygen content of the water is affected by several factors including the following:
- The Nature of the Water
Oxygen from the air is dissolved in water at its surface, mostly through turbulence (for example, waves, riffles, water tumbling over rocks, etc). For this reason, fast-moving water (such as a stream) will have a higher oxygen content than stagnant water.
If water is very stagnant, oxygen only dissolves on the water’s surface, and anything below the upper layer of the water will have a low oxygen content.
- Presence or Absence of Aquatic Plants and Algae
Aquatic plants and algae also affect how dissolved oxygen is in a body of water. During the daylight hours, they produce oxygen through photosynthesis and release it into the water.
At night, aquatic plants and algae will use up dissolved oxygen in the water via aerobic respiration and release carbon dioxide into the water.
For these reasons, the concentrations of dissolved oxygen in water with lots of photosynthesizing aquatic vegetation will be highest in the mid-to-late afternoon when photosynthesis rates are greatest and will reach the lowest concentrations just before the sun rises the next morning.
- How Much Dead Matter /Waste Is the Water
Water with lots of decaying plants and other organic matter (Sewage, yard waste, etc) will have a lower oxygen content. This is because the bacteria responsible for the process of decomposition use oxygen and release carbon dioxide into the water, reducing the oxygen content of the water.
- Altitude/Atmospheric Pressure
Water at lower altitudes can hold more dissolved oxygen than water at higher altitudes. With rising altitude, the atmospheric pressure decreases – hence less oxygen can dissolve into water.
For this reason, water at higher altitudes typically has less dissolved oxygen than water at lower altitudes.
- The Concentration of Dissolved Salts Present in the Water (Salinity)
Water with a high mineral content (high salinity) can hold less dissolved oxygen than water with a low mineral content (low salinity).
2. Temperature
Like all amphibians, toads are cold-blooded (ectothermic) animals.
This means they cannot internally regulate their body temperature. Instead, their body temperature changes with the temperature in their surroundings.
In other, their environment is the main influence on their body temperature.
For example, a toad swimming in 30°C (86°F) water has a body temperature very close to 30°C. In water at 15°C (59°F), the body temperature of the same toad is around 15°C.
Being ectothermic means toads will have a varied rate of metabolism, depending on the water temperature.
Warmer water temperatures increase metabolic rates. This means toads have to resurface more often to get oxygen.
On the opposite end, cooler water allows toads to conserve oxygen. This extends the time they can hold their breath.
All this combined means toads can stay underwater at lower temperatures for much longer than they can at warmer temperatures.
3. Species
Tadpoles have gills that provide a very large surface area to absorb lots of oxygen from the water. However, as adults, frogs do not have gills, so how much oxygen they can absorb from the water depends on their skin surface area.
Some toad species are more adept at holding their breath than others and thus can stay underwater longer.
4. How Active the Toad Is
Activity affects how much oxygen the body needs.
Think about it. When you are running or jogging, you breathe in much quicker breaths than when you are lying on the couch.
For toads, this is also true. Their oxygen demands will be influenced by their activity levels.
A toad that is resting on the bottom of the water may be able to stay submerged for several hours.
On the other hand, an individual of the same species who is escaping a predator may only be able to stay underwater for a few minutes before needing to surface to replenish its oxygen supply.
Frequently Asked Questions (FAQS)
Can toads drown in water? Toads can drown in water, Even with their ability to breathe underwater through their skin. They have lungs, and If their lungs fill with water, they can drown.
Can toads drown in a pool? Toads can drown in a pond if they fall in and have no way of getting out of the water. They have very absorbent skins, so chlorine and other chemicals found in pools can penetrate their skin and seriously harm or even kill them.