Leap 6 (Weeks 34–37): Sorting the World and Stranger Wariness
For general reference only, not medical advice. Every baby develops at their own pace. If you are worried about your baby, contact a doctor or other health professional.
At around eight months many babies become noticeably more selective. They know exactly who their main caregivers are and may cry when anyone else tries to hold them. Crawling, pulling up to stand and new sleep disruptions often arrive at about the same time.
This page describes what is typical in this window and how to support your baby’s growing independence while keeping them feeling secure.
Typical timing
The sixth window is usually given as weeks 34 to 37 from the due date, roughly the eighth month for a baby born on time. Babies born early tend to reach it later after birth.
Separation anxiety tends to rise between about eight and eighteen months in many children, so the feelings that appear here may come and go for a long time. A short window on the calendar does not mean the clinginess will always end on schedule.
What parents may notice
- Crying when held by unfamiliar people or when a parent leaves.
- Waking at night and wanting a parent, even after a period of good sleep.
- Crawling, scooting, pulling up on furniture and getting stuck standing.
- Practising new movements at night, such as sitting or standing in the crib.
- Careful examination of small things: picking up crumbs, poking holes, turning objects over.
- Responding to their own name and to familiar words such as “bath” or “no”.
What is developing
Babies at this age start to sort what they see into groups. Dogs are different from cats, food is different from toys, and familiar people are clearly different from strangers. This ability to recognise categories is a big step in thinking, and it explains why a baby who used to smile at everyone may now become wary of new faces.
Movement is changing fast as well. Many babies crawl in some form, pull themselves to stand and start using a pincer grasp to pick up small objects between the thumb and finger. New movement skills are often practised everywhere, including in bed, which can disturb sleep.
Practical ways to help
- Offer sorting games, such as putting blocks into a box, taking them out, or separating balls from cups.
- Name the categories your baby is noticing: “That is a dog. That dog is big. That dog is small.”
- Give new adults time to warm up, and let your baby approach rather than being picked up straight away.
- Keep a short, predictable goodbye routine for childcare or when leaving the room.
- Help your baby practise sitting back down from standing during the day so they can do it themselves at night.
- Read simple picture books and point to familiar things.
- Keep night visits calm and brief, with the same comforting words each time.
Sleep, feeding and safety
Now is a good time to childproof. Get down to your baby’s level and look for small objects that could be swallowed, button batteries, cords and blinds, unstable furniture that should be anchored, and stairs that need gates. Babies at this age put almost everything in their mouths.
Lower the crib mattress once your baby can sit or pull up, and remove anything that could be used to climb out. A transitional object, such as a small, safe comfort item, is generally only recommended in the sleep space after twelve months; before that, keep the crib clear.
When to consult a doctor
Talk to your doctor if your baby is not yet sitting with support, does not babble, does not respond to their name, does not look where you point, or does not seem to recognise familiar people by around nine months. A loss of skills your baby already had always deserves prompt attention.
Seek medical advice for fever with unusual drowsiness, breathing difficulty, repeated vomiting, signs of dehydration or any injury from a fall, especially to the head.
Whatever the calendar says, seek urgent medical help for difficulty breathing, blue or very pale lips or skin, a baby who is unusually floppy or hard to wake, a seizure, a rash that does not fade when pressed, signs of dehydration such as very few wet diapers, repeated forceful vomiting, or a fever of 38°C (100.4°F) or higher in a baby under three months. Trust your instincts: if you feel something is wrong, contact a doctor or emergency service.