Why Do Some Babies Never Crawl?

Crawling is so closely associated with babyhood that many parents panic when their infant shows no interest in it. But a substantial number of healthy babies never crawl on their hands and knees at all. They scoot on their bottoms, roll across rooms, drag themselves commando-style, or simply skip straight to pulling up and walking. The variability is so well established that the CDC removed crawling from its developmental milestone checklists entirely, a move that surprised many parents but reflected decades of research showing that crawling is one of the most inconsistent milestones in early childhood.

Why Crawling Was Dropped from the Official Milestones

In 2022, the CDC revised its “Learn the Signs. Act Early.” program, and one of the more notable changes was the removal of hands-and-knees crawling from the milestone checklists. The reasoning was straightforward: the evidence shows crawling is highly variable across cultures and individuals, and normative data on when it “should” happen are thin compared to milestones like sitting unsupported or walking.¹ The CDC’s goal was to simplify materials for families and ensure every milestone on the list had solid evidence-based timing behind it. Crawling didn’t meet that bar.²

This doesn’t mean pediatricians stopped caring about how babies move. It means the specific act of getting up on hands and knees is no longer treated as a pass/fail checkpoint. What clinicians look for instead is whether a baby is developing some form of independent mobility on the floor, whether that’s classic crawling, belly crawling, scooting, or another pattern. The milestone that matters is the ability to get from point A to point B, not the particular posture used to do it.

The Many Ways Babies Get Around

Hands-and-knees crawling gets the most attention, but babies have a surprisingly wide repertoire of floor locomotion. Bottom shuffling, where a baby sits upright and scoots forward using their legs and sometimes one hand, is one of the most common alternatives. In a Japanese study of 241 typically developing infants, about one in five exhibited bottom shuffling between 6 and 18 months of age. Interestingly, the age at which these babies achieved other milestones like sitting unsupported or even traditional crawling didn’t differ from non-shufflers.³ Bottom shuffling appears to be a preference, not a deficit.

Other babies army-crawl on their bellies, pulling themselves forward with their arms while their legs drag behind. Some roll end over end to reach a toy. A few adopt a bear-walk stance, moving on hands and feet with straight knees. And some babies barely do any of these things before hauling themselves upright using furniture and cruising along edges until they take their first independent steps. Each of these patterns represents a valid solution to the same problem: how do I move my body through space before I can walk?

What Pushes Babies Toward or Away from Crawling

Whether a baby crawls on hands and knees, scoots, or skips floor locomotion altogether depends on a tangle of factors, none of which parents have complete control over.

Floor time is one of the biggest levers. Babies who spend more awake time on the floor, especially on their stomachs, get more opportunities to build the upper-body and core strength that hands-and-knees crawling demands. Tummy time has been shown to positively affect gross motor development, including the ability to move while prone, roll, and crawl.⁴ One study found that structured tummy time exercise significantly improved gross motor skills in babies aged 3 to 6 months.⁵ The connection is intuitive: a baby who rarely lies on their stomach has less reason to figure out how to push up, pivot, or lunge forward.

Equipment matters too. Baby walkers, which position infants upright and let them scoot around on wheels, appear to reduce the likelihood of crawling. One study found that babies who used walkers were three times more likely to skip crawling entirely compared to those who didn’t use walkers.⁶ The mechanism is probably straightforward: walkers let babies experience upright mobility before they’ve worked through the prone stages, so the motivation to figure out hands-and-knees movement fades.

Even diapers play a role, though a modest one. Research has shown that the shape and bulk of a standard disposable diaper can restrict spontaneous lower-limb movements in young infants. Babies wearing normal diapers moved their legs less freely than babies who were naked, and the width of the diaper’s crotch area affected the range of knee movement.⁷ Nobody is suggesting parents ditch diapers, but it’s a reminder that the physical environment around an infant’s body shapes how that body learns to move.

How Culture Shapes Motor Milestones

Cross-cultural research reveals just how much childrearing practices influence whether and when babies crawl. In Tajikistan, many families use a traditional cradle called a gahvora, which holds the baby in a supine position for extended periods during the day. Infants raised with heavy gahvora use showed later motor onset ages compared to World Health Organization standards, and the amount of time spent cradled predicted the age at which babies began walking, as well as the proficiency of their sitting, crawling, and walking.⁸

Similar patterns emerge worldwide. In cultures where babies spend much of their early life being carried on a parent’s body or seated in a caregiver’s lap, crawling may appear later, appear briefly, or not appear at all. The babies still learn to walk, usually within the normal range, but the floor-based stages of motor development simply get compressed or bypassed. This isn’t pathology. It’s a reflection of how flexible human motor development actually is.

Parental expectations can have a subtler influence as well. In the Japanese bottom-shuffling study, parents who believed their baby should learn to sit right after rolling over had a significantly higher rate of bottom shuffling in their infants, with about 27% of those babies scooting on their bottoms compared to the overall rate of roughly 22%.³ The researchers suggested that these parents may have positioned their babies in sitting earlier, giving the infants the opportunity to discover scooting as a movement strategy before they ever tried crawling.

When Skipping Crawling Deserves a Closer Look

For the majority of babies who skip or delay crawling, there’s nothing medically concerning going on. But in a smaller subset, absent or significantly delayed crawling can be one piece of a larger pattern worth discussing with a pediatrician. The key is context: a baby who isn’t crawling at 10 months but is sitting independently, reaching for objects, and showing interest in moving is in a very different situation from a baby who isn’t crawling and also isn’t sitting, isn’t bearing weight on their legs, or has unusually stiff or floppy muscle tone.

A large population-based study found that a one-month delay in crawling onset was associated with a 5 to 14% increased risk of significant overall motor impairment later on, depending on the statistical model used. Delays in walking onset carried an even stronger signal, with each one-month delay linked to a roughly 22% increased risk of overall motor impairment and a longer transition from crawling to walking associated with higher risk of gross motor difficulties.⁹ These findings don’t mean that any baby who crawls late is destined for motor problems. They mean that late crawling in combination with other delays can serve as an early signal that warrants monitoring.

Conditions where crawling may be absent or abnormal include cerebral palsy, certain genetic syndromes, and significant hypotonia (low muscle tone). In these cases, the absence of crawling is rarely the only red flag. There are usually other signs: difficulty holding the head up, not bearing weight through the arms, limited interest in reaching, or asymmetrical movement patterns where one side of the body works very differently from the other.

Retained Reflexes and Motor Development

Babies are born with a set of primitive reflexes, involuntary movement patterns that normally fade during the first year as the brain matures and voluntary motor control takes over. When these reflexes persist beyond their expected window, they can interfere with the development of more complex movements like crawling. A systematic review found a significant inverse relationship between retained primitive reflexes and motor skills in preschool-aged children: kids with persistent reflexes such as the tonic neck reflex, tonic labyrinthine reflex, and Moro reflex showed poorer gross and fine motor performance, including problems with balance, coordination, and posture.¹⁰

This doesn’t mean that every baby who skips crawling has retained reflexes. But it helps explain one of the neurological mechanisms that can make crawling difficult or impossible for some infants. A baby whose tonic neck reflex is still active, for example, will automatically turn their head and extend one arm whenever they try to get into a crawling position, which makes coordinated hands-and-knees movement extremely awkward. These babies often find alternative strategies, like scooting or rolling, that work around the reflex.

Does It Matter in the Long Run?

This is the question parents really want answered, and the honest answer is that for the vast majority of babies, skipping crawling has no lasting consequences. Research on crawling patterns in people who stopped crawling decades ago found that old crawling patterns were retained despite years of disuse. More surprisingly, when adults and older children who hadn’t crawled in years were asked to crawl again, they hadn’t lost anything. Their gait patterns, the limbs they used for support, and their crawling speed were strikingly similar to those of babies who were actively crawling, despite enormous differences in body size and years of practice.¹¹ The motor program for crawling seems to be deeply encoded once it’s established, and new movement features can be added on top of it over time.

But what about babies who never established the pattern in the first place? The evidence here is reassuring. Studies tracking babies who shuffled, rolled, or walked early without crawling generally find no meaningful differences in later gross motor skills, cognitive development, or academic performance. The concern you’ll sometimes see online, that skipping crawling causes learning disabilities or problems with left-right brain coordination, is not well supported by research. It gets repeated often enough that some parents feel genuinely anxious about it, but the claims tend to originate from therapeutic traditions rather than controlled studies.

One interesting wrinkle involves visual-spatial perception. Research from the 1980s found that crawling-onset age, rather than the total amount of crawling experience, predicted whether infants would avoid a visual cliff, a transparent surface over an apparent drop-off. Babies who started crawling earlier were more cautious about the apparent danger, suggesting that crawling may interact with depth perception in ways that aren’t fully explained by simple practice.¹² This finding raises questions about the perceptual consequences of different locomotion strategies, but it doesn’t establish that babies who skip crawling have lasting perceptual deficits.

The Role of Earlier Crawling Patterns

One misconception is that crawling is a single skill that either appears or doesn’t. In reality, most babies cycle through multiple crawling-like postures before settling on hands-and-knees movement. They may rock on all fours for weeks. They may belly-crawl for a month, then transition. Research on this progression found that experience with earlier crawling patterns, like belly crawling or rocking, appeared to have beneficial effects on hands-and-knees crawling by strengthening the underlying components common to all forms of crawling posture. Differences in age or body dimensions alone couldn’t explain the transition.¹³

This suggests that babies who go straight to bottom shuffling or standing may simply have bypassed the sequence of prone positions that typically leads to hands-and-knees crawling. Once a baby discovers an efficient way to get around, whether that’s scooting or cruising along furniture, there’s little incentive to go back and try a more effortful posture. Babies are pragmatists. They use whatever works.

How Crawling Fits into Human Evolution

From an evolutionary standpoint, hands-and-knees crawling is something of a human specialty. Chimpanzees, our closest living relatives, don’t crawl on their hands and knees as infants. Young chimps go through a brief palmigrade phase (walking on flat palms) before transitioning to knuckle-walking.¹⁴ The hypothesis is that as hominin legs lengthened over millions of years of selection for bipedalism, infant locomotion was reshaped too. Hands-and-knees crawling appears to have derived from that earlier palmigrade quadrupedalism, modified to accommodate longer legs and a more upright body plan.

Researchers have proposed that evolutionary changes in crawling, sitting, and pointing all contributed to the progressive development of both locomotion and advanced cognition in the human lineage.¹⁵ The idea is that the prone position and the coordinated limb movements of crawling may have helped scaffold the neural wiring that later supports walking, tool use, and spatial reasoning. Whether this evolutionary history means that individual babies who skip crawling miss out on something is a separate question, and the evidence so far doesn’t support that interpretation. Evolutionary legacies describe population-level patterns, not individual requirements.

Practical Guidance for Parents

If your baby isn’t crawling and you’d like to encourage floor mobility, the most effective thing you can do is offer more supervised floor time, especially tummy time during waking hours. Place interesting toys just out of reach. Get down on the floor yourself so the baby has a reason to move toward something. Limit the time spent in containers like bouncy seats, swings, and walkers, all of which keep the baby in a fixed position and reduce the need to problem-solve with their body.

If your baby has settled into an alternative movement pattern like bottom shuffling, there’s no need to try to “fix” it. As long as your baby is mobile, interactive, and meeting other milestones like reaching, babbling, and responding to their name, the specific style of floor locomotion is a matter of individual preference, not a medical issue.

The situations that warrant a conversation with your pediatrician include a baby who isn’t mobile by any means at 12 months, a baby who consistently favors one side of the body, a baby who seems to be losing skills they once had, or a baby who shows very stiff or very floppy muscle tone. In these cases, the absence of crawling is a symptom to investigate, not a diagnosis by itself. Early evaluation can connect families with physical therapy or other interventions if needed, and the earlier that happens, the better the outcomes tend to be.