Despite its small size it is a very vocal little animal.
They give a range of calls ranging from grunts, clicks and crackles.
Their long-range, territorial call sounds just like a wailing human child.
This together with the "cute" face may account for the name "bush baby."
An African bush baby obviously have very distinctive, forward facing eyes that are enormous.
Its eyes are so large in relation to its head that they cannot move them in their sockets.
If they want to shift their gaze they have to turn their whole head.
Consequently they are able to look directly backwards over their shoulders.
Taken by larger owl species, snakes, servals, African wild cats and genets.
Using its large ears a bush baby can locate prey by sound so precisely that it can catch flying insects from the air.
They are fast, agile and very accurate.
This allows them to catch insect prey in the dark by snatching them from the air.
In line with their nocturnal habits bush babies make heavy use of scent signals.
They have an unusual and elaborate way of scent marking, which is called urine washing.
This process involves dribbling urine over their hands and feet and then rubbing them together.
Subsequently they leave a trail of damp, smelly foot and hand prints along their pathways as they move through the branches.
The sticky urine also gives them a better grip as they jump between branches.
Individuals have overlapping home ranges that they mark with chest gland secretions.
The thick tailed version is more than twice as large and eight times heavier than the lesser bush baby.
It also has a more pointed face and a longer, bushier tail.
Thick-tailed bush babies are exceptionally agile climbers and leapers.
They live in groups of two to six, consisting of an adult male with females and their young.
They sleep together in thick foliage up to 12 m above the ground.
They usually forage alone but in fruit clusters will feed together in groups where they tolerate each other.
They will even occasionally indulge in grooming sessions.
These interactions are mostly common during summer when food is more abundant and there is less competition because it is outside the mating season.
Thick-tailed bush babies walk along branches whereas lesser bush babies hop and jump more freely.
Lesser bush babies have a range of at least 25 calls.
They cluck and chatter when encountering intruders.
The alarm call is a shrill whistle and males cluck when following a female on heat.
Males check the reproductive condition of females by sniffing their genitals.
Males fight savagely and a loser that cannot escape may be killed.
A female on heat aggressively repulses the male's first approaches.
When she does finally allow it, mating takes place repeatedly for about five minutes every two hours.
A mother stays continuously with her babies for their first three days.
The young are weaned at six weeks and are independent at two months.
Young males disperse a few kilometers from their birthplace while females often remain in their natal group.