Careful of their swarm in Lava caves they will gank you and quickly surround you and push u just little on every hit ... Make sure you have wall behind you and stand with your back against it while fighting them ... Or else Lava ...

This is a great guard tame get at least 5 or 6 and have them placed inside of a house and if someone breaks in they will kill the enemies very fast and very effectively

Some of the bats are infected with super mega rabies witch will massacre you and if you have it you will infecte anyone near

Bug repellant is not a necessity, it can be replaced by crawling and using a ghillie suit. This works on all passive cave tames.

Mainly used in PvP to destroy player's armor, the Onyc is a guard animal. To maximize efectiveness upgrade health, damage, and speed.

Nah nah nah nah nah nah nah nah batman!!!!!

These bats stop me from raiding my arch enemy’s base they killed all my dinos which included 13 Rexs and 7 of my tribe mates came with me and died extremely quickly. Please vote up to warn others

I have 8 very high level bats protecting my Dino pen and during an offline raid on me the bats swarmed the three raiders and managed to kill all three of them. The had journeyman Flak and mastercraft weaponry. So in the near future I will be taming many more of them

Two words:
Flame Thrower

Can be found in the Magmasaur cave of Genesis.

Probably the easiest way to tame theses guys is to make a 1 foundation hut, draw him to it, get him stuck by placing down your last wall, walk away until you lose agro, then use bug repellent

When the onyc sees you, it will slowly fly towards you. However, if you attack it, onyc will fly much faster until killed or you go out of targeting range.

Found in almost any cave, the Onyc is an absolute nightmare for the unprepared.

Its a great creature for Defense and protecting bases.

It's a slower, but more accurate and powerful version of the Dimorph. It can't carry a lot, move fast or take down larger creatures. but a good distraction/sacrificial lamb or decorative pet.

Some caves are untamable bats, while others are fine, wiki page has a map

Lots of them at the jungle castle in ragnarok, but most of them are too high level to tame; I found a level around 450 there

If trying to tame on center be careful cause it may fly up into the skybox right when it is tamed.
Source: Happened to me.

I am a failure and we all know it

Bats now deserve some new levels of respect. Like their fellow Cave dweller the Megalania, they have a chance to infect you with Mega Rabies (though only a chance rather the 100% like Megalania)

They are easy to spot and avoid using bug repellent. But due to the new Biological weapon element of them. Engage at a distance where possible. Fight them with sword and pike only as a last resort. Make sure you have a stock of Antidotes or Wyvern Milk before any Splunking