"hot spot" vs "hot end"

[Bl69aze]

Hi guys, I just had a thought for you reptilian experts (looking at you Sdaji )

Do you consider a Hot end different to a basking spot? I.E people say "your hot end should be 32 and cool end should be 24-25"

Now in that hot end, would you have a Hot spot/basking spot that's a couple of degrees hotter; say 35-36? Or do you consider making the basking spot 32, which would make the air temp hotter/colder depending on the heat source (I'm too tired to think) in the hot end?

I ask this, as I noticed my new enclosures hot side has a spot where it gets to 36-37 degrees even if I set thermostat prob to 34 - These are Bredli, so I'm not too worried about the temp changes through hot end, I've heat gunned the whole enclosure and cool end doesn't get affected by hot end temps. However, the previous used these same enclosures for the same species, and from my understanding is that, within reason (nothing above 40), it doesn't matter how hot the hot spot gets, as they can just slide out if they get too hot to thermoregulate

TL;DR
Do you guys reckon somewhere in the "hot end 32" blahblah there should be an accessible spot of higher temps in the range of 35-36+?

Cheers ^_^

 

[Sdaji]

This is probably a good question, a good topic to discuss. Temperature is the #1 thing a reptile keeper should understand, but it's something most people don't focus anywhere near enough on.

Yes, absolutely, a hot end and a basking spot are two different things. In some cases they may perform the same function, but often the difference is important.

Broadly speaking, temperature/heat movement can come in three different forms: Conductive, convective and radiant. Maybe for the purpose of thinking about reptile keeping we could also call one 'ambient'.

Quickly looking at these, conductive heat is where two objects touch and heat is transferred from the hotter object to the cooler object. Floor heat from heat mats or cords works in this way, and similar conditions exist in nature such as when a snake sits on a rock at night which is still warm because it was in the sun, or when a lizard sits under a rock which is in direct sun.

Convective heat is not relevant to reptile keeping. An example is when hot water is poured into a cold fluid and the heat is given to the other fluid. Forget this one.

Radiant heat is what we are talking about with basking spots. Radiant heat is what you feel when you stand in full sunshine or by a fire. You can have very cold air, you can be outside at night in sub zero air, but the heat from the fire keeps you warm. Without actually touching the fire, even though the air in between the fire and your hand is below zero degrees (or very cold), you can actually burn your hand. The sun works in a similar way. The sun is incredibly hot, the empty space between the sun and the Earth is incredibly cold, and the radiant heat travels along and remains inactive until it hits something, whether that's you, a cloud, a rock, a snake, or anything else. This can allow natural basking spots of 50-60 degrees or more even on cold days where the air temperature is only around 10 degrees. A spotlight works in a similar way to the sun or a fire. It emits radiant heat which travels until it hits an object, heating it up, which creates a basking spot considerably higher than the air in that area. So, the hot end (or if you wanted to be silly and put a lot of effort in you could even put it at the cold end) may be, say, 25 degrees (this is measuring the air temperature), but the basking spot could be, say, 40-50+ degrees (we usually measure this by taking the temperature of an object, such as the surface of a rock, directly under the radiant heat source).

Often, people incorrectly refer to hot spots from non radiant heat sources such as heat mats as basking spots. This clearly causes confusion.

We can also think of ambient temperature, which just means the background air temperature (and all the objects in that air, including reptiles, which are not in contact with a conductive heat source or exposed to a radiant heat source will be more or less at the same temperature). This is the important way we heat many tropical species which do not naturally bask in sunlight.

 

[Aido09]

Very well said. Much appreciated.