Newts are adolescent Freakers.
Newts are adolescent children or teenagers infected with the "Freaker Virus." They appear to be ranging in age from ten through fourteen, and have a height between 55 inches to 62.5 inches. Though occasionally bipedal, Newts will usually crawl on all fours when they move or attack. Like the adult Freakers, their skin are discolored and their internal structure are somewhat visible. However, a unique characteristic that the Newts have apart from any other Freaker is still retaining hair. This could be from a late-stage symptom of the virus causing hair loss not yet being fully active in Newts.
The Newts encountered in-game are among the few infected children that survived the infection and other Freakers. It is believed that these survivors adapted as to not make the same mistakes as the deceased (i.e. generally avoiding other creatures, forming packs, stealing supplies).
Newts are "opportunistic hunters" that will only attack Deacon if he is low health or engages them. They also apparently, as stated by some of the Days Gone creators, tend to avoid larger Freakers. They seem to have a sense of self preservation exemplified by them waiting for a good opportunity to strike, rather than attacking Deacon head on like the other variants of Freakers would.
As stated, they will avoid Deacon or observe him from a distance if he has a good amount of health. Newts also appear to be very agile, scaling structures to run away or position themselves for attack. It would make logical sense for Newts to follow similar behavioral patterns as the other Freakers (e.g. needing food, drink and hibernating).
Newts generally avoid conflict with others until the opportunity arises but if a Screamer wanders too close, they will attack - while a Newt is half the size of the Screamer, the Newt is still capable of taking her down in a few swipes.
Little strategy is required when it comes to these small creatures. They can easily be picked off by a crossbow or gun and can be easily killed in one or two strikes from a decent melee weapon. Newts, just like Swarmers, tend to hang around areas in ‘packs‘ of three or more but unlike Swarmers, tend to stay together and don’t wander far from each other sometimes making them easy to kill together with a well aimed explosive or Molotov. Be wary of getting into close quarters with a pack of Newts, as while weak, they will attack on opportunity. Newts, if on a roof, will often avoid fighting altogether if Deacon is on the ground below.
It can be useful to note that Newts, unlike most other enemies in the game, cannot be normally affected by the special bolt from the Crossbow. Being shot by a special bolt will simply cause the Newt to convulse and die and will not influence it to attack other enemies. A special bolt will kill off a Newt faster than any other enemy in the game.