6 Weird Baby Behaviors Explained

Did your baby just let out a fake cough? Experts shed light on your baby's most peculiar habits, from arm flailing to fake coughing.

baby standing with help of a bench

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Adorable as they are, babies can be wildly unpredictable, too. They have immature nervous systems, zero life experience, and, let's face it, not a lot of social awareness. So it's no surprise they do things that make no sense to parents.

Read on to learn about six weird but common behaviors you might notice from your baby, from flailing arms to fake coughs. By learning the developmental basis for these head-scratching habits, you can better understand your baby as they grow.

1. Flailing Their Arms When Startled

Babies spend a lot of time in their parent's arms—from which a fall could be fatal. So, babies adapted by developing a defensive strategy against getting dropped. At least, that's how some experts think an automatic behavior called the Moro reflex came to be.

When your infant has the sensation that they're falling or if they're startled, they may fling their arms out to either side as though they're trying to fly. If someone had lost their grip on a baby, this reflex may help the baby hang on and buy the caregiver a few extra seconds to catch them, says De Ann Davies, a former child development programs director at Phoenix Children's Hospital.

While it's startling to see, this reflex is a sign that your little one's nervous system is developing properly. Still, "it's stressful on the infant," says Peter Vishton, PhD, associate professor of psychological sciences at the College of William & Mary in Williamsburg, Virginia. Their breathing and heart rate will temporarily go up. But don't worry: Babies typically stop exhibiting this reflex by 3 months.

2. Trembling and Shivering

One minute, your baby's lying there calmly. The next, they're trembling like you did when you got your nursery-furniture bill. What's going on? It's a nervous system blip, explains Davies. "Neurologically, babies are just not very good at regulating their movement at first, and you may see a little jerkiness," she says. It's normal for newborns to tremble when crying or twitch when sleeping, in particular.

Of course, check their hands to see if they feel cold. Because their ratio of skin surface area to weight is lower than adults', your baby will lose their body heat about four times faster than you do. Preemies are especially vulnerable to cold. That's where trembling comes in handy: When muscles tense and relax rapidly, it generates heat. A good rule of thumb is to dress your baby similarly to how you're dressed then add an extra layer.

If your child trembles often, that's worth a call to their doctor. Some research has linked jitteriness and tremors to a vitamin D deficiency.

3. Fake Coughing

Out of nowhere, you hear your baby start hacking. Naturally, you rush to see what's wrong, and the answer is—nothing! They may grin mischievously as they loudly and theatrically cough again.

This common baby gag is proof your baby is becoming more socially aware. "Around 6 months, when the fake coughing first begins, babies are really starting to get how the world works," says Dr. Vishton. "Your child has noticed that when someone coughs, you're very solicitous, so [they're] doing it to get some attention." So give them the interaction they crave—smile and even fake cough back. "There's no harm," says Dr. Vishton. "It's just hilarious."

4. Touching Their Genitals

It's time for a diaper change, so you remove your baby's diaper. Except this time, your baby doesn't just lie there; their hands wander south and stay there. What's going on?

"It's common to see babies start playing with their genitals around the 5- to 7-month mark," says Davies. "It means something very different to them than it does to you, I promise!" Babies are driven to touch themselves out of simple curiosity, she explains. "They're such eager learners and explorers at that age—anything they can get their hands on is fair game."

Their natural curiosity includes themselves and their various body parts. "If you think about it, your child is also playing a lot with [their] hands and feet, but it doesn't attract your attention the way it does when [they] touch [their] genitals," adds Dr. Vishton. Your baby may spend more time on their genitals than on other places simply because it feels good.

It's important to remember that genitals are just body parts like everything else, so avoid reactions that might induce shame. Instead, adopt a body-neutral approach. For example, if your little one reaches down during a diaper change, hand them a toy so they have something different to occupy their attention. Or go with the flow. "Accept that touching themselves is something kids do, and it's just another way of learning about their bodies," Davies says.

5. Standing (And Staying There)

Around 10 months, your baby will hit a cool milestone: They'll grab onto a piece of furniture and pull themselves up onto their feet. Unfortunately, this exciting turn of events can have a downside—they may be unable to figure out how to sit back down again!

Lowering your butt back down takes practice and coordination. So get ready: "You may be awakened at night by a crying baby who's stranded upright, holding on to the side of [their] crib," Davies says.

It's OK to offer a helping hand, but don't rush to sweep them off their feet altogether. "Sitting is a skill they need to learn for themselves," Dr. Vishton explains. The chances they'll hurt themselves are small since babies have those cushy tushies (and diapers) for padding. During the day, position them next to a safe surface to pull up on (like the edge of a sturdy sofa) and put down a pillow. Soon they'll move up and down with confidence.

6. Forgetting Their New Tricks

You may have cheered when your baby first shook a rattle or rolled over. So, why do they look at you quizzically when you hand them their Wiggly Giggler or gently nudge them toward a roll? Could they have forgotten their new skill?

Babies temporarily forget new skills the way you forget things you thought you knew, like how to reboot your TV, says Dr. Vishton. "Sometimes, even after we've successfully performed a task several times, we have an incomplete memory of how we accomplished it," he explains. Eventually, fundamental skills will become second nature. (Children with a developmental delay may need extra help getting there.)

Another possibility is that a new setting—say, Grandma's house instead of yours—could disorient them. Or their mind is occupied by a new challenge. "Sometimes it's a good thing when it seems like your child abruptly stopped doing something [they've] learned, even if they didn't learn it so long ago—it means [they're] moving on," Davies says.

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Sources
Parents uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Newborn Reflexes and Behavior. Seattle Children's. 2023.

  2. Warmth and Temperature Regulation. Children's Hospital of Philadelphia. n.d.

  3. Benign Neonatal Shudders, Shivers, Jitteriness, or Tremors: Early Signs of Vitamin D Deficiency. Pediatrics. 2017.

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