Table of Contents
Juvenile animals are not simply “small adults.” Their behavior reflects special needs, vulnerabilities, and learning tasks that occur only during early life. While the parent chapter introduced how behavior develops over an individual’s lifetime (ontogeny), this chapter focuses specifically on what is characteristic and unique about the behavior of young animals.
Why Juvenile Behavior Is Special
Young animals face three fundamental challenges:
- Survival despite vulnerability
Bodies and senses are still developing; movement is often clumsy. Behavior must reduce risks (predators, starvation, accidents). - Learning and practice
Complex adult skills (finding food, social interaction, courtship, territory defense) rarely appear fully formed. Juveniles must practice and refine them. - Securing care from adults
Many species provide parental care. Juvenile behavior often functions to elicit and maintain this care.
Because of these challenges, juvenile behavior often differs systematically from adult behavior in form, intensity, and function.
Phases of Juvenile Development and Behavior
General terms (human-focused but often applied broadly) help describe juvenile phases:
- Neonatal period (newborn) – immediately after birth or hatching: strong dependence on parents, limited mobility; behavior mainly reflexive.
- Infant / Nestling period – still heavily dependent for feeding and warmth; exploration limited to close surroundings.
- Weaning / Fledging period – beginning of nutritional independence; rapid increase in exploration and play.
- Subadult / Juvenile period – body form approaches adult, but sexual maturity not yet reached; behavior dominated by social learning and practice of adult roles.
The exact sequence and length of phases vary (e.g., fish larvae vs. bird nestlings vs. mammalian infants), but in all species, behavior changes stepwise as physical and neural development progress.
Dependence and Attachment Behaviors
In many animals, early behavior is organized around staying close to caregivers, a crucial factor for survival.
Imprinting and Early Social Bonding
In some birds and mammals there is a short sensitive period soon after birth or hatching when young form strong, often irreversible, bonds:
- Filial imprinting: Young recognize and follow the mother or parent figure (e.g., ducklings following the first moving object they see that roughly matches a parent).
- Species recognition: Early visual, acoustic, and olfactory experiences help juveniles distinguish conspecifics from other species later in life.
- Attachment in mammals: Young seek proximity, show distress at separation, and are soothed by contact or familiar smells and voices of caregivers.
Key features:
- Occurs within a limited time window.
- Once formed, the bond strongly guides later social and sexual behaviors (e.g., preference for conspecifics).
Solicitation of Care
Juveniles display specific behaviors that reliably trigger parental responses:
- Vocalizations
- Bird nestlings’ begging calls; mammalian infants’ distress calls.
- Often species-specific in structure and rhythm; can signal hunger, cold, or danger.
- Postures and movements
- Open mouths, wing-fluttering in chicks.
- Reaching or clinging in primates.
- Following behavior in precocial young (e.g., lambs, calves).
- “Infant schema” (Kindchenschema)
In many vertebrates, round heads, large eyes, and certain facial proportions elicit caring behavior from adults (particularly parents). This is a morphological feature, but is tightly linked to how adults behave toward juveniles.
These behaviors are effective because they tap into strong parental response patterns shaped by natural selection.
Exploration and Curiosity
Juveniles show marked exploration behavior:
- Increased tendency to:
- Move around new environments.
- Investigate novel objects and sounds.
- Manipulate items (biting, touching, shaking, pecking).
Functions:
- Information gathering: Learning where resources and shelters are.
- Sensorimotor calibration: Adjusting movement, perception, and coordination to the environment.
- Risk assessment: Building “knowledge” about what is safe or dangerous.
Exploration is usually highest in intermediate stages:
- Too early: motor skills insufficient; risk too high.
- Too late: adult roles and territoriality begin to limit risky exploration.
Species differ:
- Precocial young (e.g., hoofed mammals, ground-nesting birds) explore early but usually stay within sight of adults.
- Altricial young (e.g., songbirds, many carnivores) show exploration later, after a protected nest or den phase.
Play Behavior
Play is a hallmark of many juvenile vertebrates (mammals, some birds) and even some invertebrates. Although it may look purposeless, it serves important developmental functions.
Types of Play
Common categories:
- Locomotor play
- Running, jumping, spinning, climbing, flapping.
- Seen in many mammals (e.g., lambs jumping) and birds (flight practice).
- Object play
- Carrying, shaking, throwing, and manipulating objects.
- Helps practice handling prey or tools (e.g., young predators stalking leaves or pouncing on toys).
- Social play
- Play-fighting, chasing, mock courtship.
- Often involves role reversals and self-handicapping (stronger animal does not use full strength).
Characteristics distinguishing play from serious behavior:
- Exaggerated or incomplete movements.
- Lack of immediate obvious function (no real prey, no real mating).
- Play signals:
- “Play bow” in dogs.
- Special calls in some birds and mammals.
- These signals prevent misunderstandings and aggression.
Functions of Play
Play contributes to:
- Motor development
- Refining coordination, strength, and speed.
- Cognitive flexibility
- Testing how objects and bodies behave; experimenting with new movement combinations.
- Social skills
- Learning social rules: how hard can I bite, how to read and send signals, how to resolve conflicts.
- Establishing and testing dominance hierarchies in a low-risk setting.
- Emotional regulation
- Exposure to mild, controllable stress (mock chase, mock defeat) may calibrate stress responses in adulthood.
Play tends to peak when young animals can move well but are not yet fully engaged in adult tasks (reproduction, territory defense, intensive foraging).
Learning From Parents and Conspecifics
Juvenile animals acquire many behaviors by observing or interacting with others. The general mechanisms of learning are treated elsewhere; here we focus on juvenile-specific patterns and examples.
Parental Teaching and Guided Learning
In some species, adults actively facilitate learning:
- Food-related teaching
- Meerkats provide young with increasingly dangerous prey (scorpions first disabled, then intact).
- Raptors and felids may bring live but weakened prey for juveniles to practice hunting.
- Skill demonstration
- Some birds demonstrate nest-building or foraging sites.
- Cetaceans (e.g., dolphins) may show juveniles specific hunting methods.
Teaching is characterized by adult behavior changing in the presence of naïve young in a way that accelerates juvenile learning, often at some cost to the adult.
Social and Observational Learning
Juveniles often:
- Mimic foraging techniques
- Young chimps copy nut-cracking with stones.
- Young birds learn what to eat by watching parents and flock members.
- Adopt local cultural traditions
- Dialects in bird song.
- Tool-use variants in primate groups.
- Specific migration routes in some birds and mammals.
Sensitive Periods for Learning
Some skills can only be acquired normally during a limited sensitive period in juvenile life:
- Song learning in songbirds
- Young birds must hear adult song during a specific time window to later produce species-typical song.
- Social preferences and mate choice
- Early experiences can shape which individuals are later regarded as potential mates or allies.
Outside such periods, learning may be incomplete or impossible, or require much more effort.
Juvenile Social Behavior and Group Structures
The social environment of juveniles often differs from that of adults.
Peer Groups and Play Groups
- Many juveniles form age-structured groups (e.g., crèches in some birds, juvenile bands in primates).
- These groups:
- Provide opportunities for social play and practice of communication.
- Reduce individual predation risk (many eyes vigilant).
- Allow learning of group-specific social norms.
Hierarchies and Role Practice
Juveniles frequently engage in:
- Mock fights and chases:
- Testing strength and asserting or accepting rank.
- Learning when to submit and when to persist.
- Practice of adult roles:
- Young predators stalk and pounce.
- Young social mammals may engage in “pseudo-parental” behavior with younger animals.
Juvenile hierarchies are often more fluid than adult ones, but they can foreshadow later dominance relations.
Species Differences in Juvenile Strategies
Life-history patterns strongly shape juvenile behavior.
Precocial vs. Altricial Species
- Precocial young (e.g., ungulates, shorebirds):
- Born or hatched well developed; can walk or run soon after birth.
- Juvenile behavior emphasizes:
- Following parents.
- Early independent foraging (with guidance).
- Predator avoidance from the outset.
- Play often includes high-speed locomotor behaviors in open spaces.
- Altricial young (e.g., songbirds, many rodents, carnivores):
- Born or hatched helpless, often blind and naked.
- Early behavior centered on:
- Begging for food.
- Seeking warmth and contact.
- Exploration and play are delayed until sensory and motor systems mature.
Solitary vs. Social Species
- Solitary adult species:
- Juvenile phase may be the main time for social contact (siblings, mother).
- Learning focuses on hunting/foraging and habitat use.
- Juveniles may disperse early to establish independent territories.
- Highly social species:
- Juveniles grow up within complex groups.
- Behavior emphasizes:
- Learning social rules and alliances.
- Communication signals.
- Cooperative behaviors (e.g., group defense, cooperative hunting).
Human-Influenced Environments
Captive or domesticated juveniles show modified behavior:
- Domestication:
- Often prolongs playful and exploratory behaviors into adulthood (neoteny).
- Can reduce fearfulness and increase reliance on humans.
- Captivity:
- Restricted environments may limit normal play and exploration.
- Can lead to abnormal repetitive behaviors if behavioral needs are unmet.
Transition to Adult Behavior
Juvenile-specific behavior gradually gives way to adult patterns as:
- Hormonal changes occur (especially around puberty).
- Body size and strength reach adult levels.
- Experience accumulates (skills become efficient and routine).
Typical changes:
- Reduction in play and increase in goal-directed activities (foraging, territorial defense).
- Shift in social roles:
- From subordinate, tolerant juvenile to adult with defined dominance status.
- Onset of courtship and mating behaviors.
The quality and variety of juvenile experiences—opportunities for secure attachment, exploration, play, and social learning—strongly influence later competence and adaptability.
Significance for Animal Welfare and Conservation
Understanding juvenile behavior has practical implications:
- Captive rearing and rehabilitation:
- Providing age-appropriate opportunities for play and exploration is essential for normal development.
- Young animals must have chances to learn species-typical foraging and social skills if they are to survive after release.
- Conservation breeding programs:
- Management of social groups and early experiences can affect successful reproduction and reintegration into wild populations.
- Domestic animal welfare:
- Early socialization in pets and livestock influences later behavior, including fear, aggression, and trainability.
Recognizing the special behavioral needs of juvenile animals is thus central not only to understanding behavior developmentally, but also to responsible interaction with animals in research, agriculture, zoos, and companion settings.