Flattie Spider: All You Need to Know in a Nutshell

The Flattie Spider is a fascinating species worth learning about. Found in warm climates, these spiders are known for their unique appearance and intriguing hunting habits. Here are the essential facts you need to know about the Flattie Spider.

These spiders are aptly named for their flat body shape, which helps them blend seamlessly into their surroundings. They exhibit clever camouflage techniques, using their physical appearance to their advantage when seeking out prey. Flattie Spiders are also known for their agile hunting skills, swiftly capturing unsuspecting insects that venture too close.

As nocturnal creatures, Flattie Spiders are most active during the night, when they employ their exceptional visual acuity to navigate in low-light conditions. Their eyesight is impressive, especially considering their relatively small size compared to other spider species. For those interested in arachnids, Flattie Spiders are a captivating subject worth further exploration.

What Are Flattie Spiders?

Taxonomic Hierarchy

Flattie spiders belong to the Animalia kingdom, in the phylum Arthropoda. They are part of the class Arachnida and the order Araneae. Their scientific family name is Selenopidae.

Family Selenopidae

Flattie spiders, or Selenopidae, are known for their crab-like appearance and flattened bodies. This unique shape allows them to fit into tight spaces, like the crevices of walls.

Some key features of Flattie spiders include:

  • Crab-like appearance with flattened bodies
  • Ability to fit into tight spaces
  • Fast and agile hunters

Other Common Names

Flattie spiders are also commonly referred to as wall crab spiders. This nickname comes from their ability to scale vertical surfaces and blend in with their surroundings.

Here’s a comparison of Flattie spiders with other spider families:

Family Common Name Body Shape Hunting Style Habitat
Selenopidae Flattie Spiders Flattened, crab-like Fast, agile Walls and crevices
Salticidae Jumping Spiders Compact, rounded Leaping Various surfaces
Theridiidae Cobweb Spiders Rounded, small Passive, venomous Corners and webs

In summary, the Flattie spider belongs to the Selenopidae family, known for their flattened, crab-like appearance. These spiders are agile hunters that can be found in crevices and on walls, earning them the nickname “wall crab spiders.”

Physical Characteristics

Fast and Agile Movement

Flattie spiders are known for their fast and agile movement. They can spin and turn quickly, making them efficient hunters. The fastest leg-driven turning maneuver ever recorded was by a flattie spider, showcasing its incredible speed.

  • Spin quickly
  • Execute fast turns

Six Eyes

Unlike most spiders, Flattie spiders have six eyes arranged in a unique pattern. This particular configuration helps them in spotting and tracking their prey more efficiently.

  • Unique eye arrangement
  • Better prey detection

Laterigrade Posture

The Flattie spider’s laterigrade posture sets them apart from other spiders. This posture involves adopting a sideways stepping pattern while moving, making their movements more unpredictable and stealthy.

  • Sideways stepping pattern
  • Unpredictable and stealthy movement
Feature Flattie Spider Typical Spider
Speed Fast Varies
Eye Count Six Eight
Posture Laterigrade Varies
Turning Maneuverability High Varies

Habitat and Range

Location and Range

The Flattie Spider, also known as the southern house spider, is commonly found in human-populated areas throughout the southern United States, including Florida. Their distribution spans numerous countries:

  • North America: United States
  • Central America: Panama, Costa Rica, Puerto Rico, Virgin Islands
  • South America: Paraguay, South Africa
  • Africa
  • Asia: Iran, India, Nepal
  • Other locations: Zambia

Environment and Preferred Habitat

Flattie Spiders are known as crevice spiders and prefer living in:

  • Warm climates
  • Cracks, crevices, or small spaces
  • Outdoors and indoors

These species find shelter in various environments:

  • Gardens
  • Homes
  • Buildings
  • Woods

Examples of Flattie Spider’s habitats:

  • Residential houses in Florida, Arizona, and Costa Rica
  • Forest edges in India and Nepal
  • Rocky regions in South Africa and Zambia

Comparison table of environments

Location Types of habitat
United States Residential houses, gardens
Central America Houses, forests
South America Gardens, woods, buildings
Africa Rocky regions, forest edges
Asia Forest edges, residential houses

Characteristic features of Flattie Spider’s preferred habitats:

  • Access to small cracks or crevices
  • Presence of a food source, like insects
  • Warm, sheltered spots

Behavior and Lifestyle

Predatory Behavior

Flattie spiders, part of the Araneomorphae group, are known for their incredible ambush skills. These wall spiders use their flat bodies to blend in with surfaces such as walls and rocks, waiting to strike their prey. Their attacks are exceptionally fast, taking place within the blink of an eye. Some examples of their prey include various insects and terrestrial animals.

Feeding Habits

These spiders rely on their camouflage and agile movements to capture their prey. They don’t create webs for catching food, instead using their stealth and speed. Flattie spiders are opportunistic feeders, consuming any suitable prey that comes within striking distance.

Seasonality and Activity Patterns

Flattie spiders can be active throughout the year, but their activity levels vary depending on the season. Here’s a brief breakdown of their patterns:

  • January – March: Lower activity due to colder temperatures.
  • April – June: Increased activity as temperatures rise and prey becomes more abundant.
  • July – September: Peak activity with optimal conditions for hunting.
  • October – December: Reduced activity as temperatures drop and prey becomes scarce.

Some fascinating characteristics of Flattie spiders:

  • Flat body shape for seamless camouflage.
  • Fast and efficient predatory behavior.
  • Opportunistic feeding habits.
  • Seasonal variation in activity levels.

In comparison to other spiders, Flattie spiders stand out for their unique hunting strategy:

Feature Flattie Spider Other Spiders
Hunting Strategy Ambush predator Use webs or active hunting
Body Shape Flat body for camouflage Various shapes and sizes
Feeding Habits Opportunistic Vary by species
Activity Patterns Seasonal variation Dependent on species and environment

In conclusion, Flattie spiders exhibit fascinating behaviors and lifestyles that make them intriguing creatures to learn about. Understanding their predatory tactics, feeding habits, and how their activity changes with the seasons helps us better appreciate their role as efficient hunters in the natural world.

Reproduction and Lifecycle

Mating and Reproduction

Flattie spiders have a unique mating process. The male spider searches for a female and communicates using a series of body vibrations. Once the female accepts, they mate.

  • Males use body vibrations to communicate
  • Females accept by responding to the vibrations

Lifecycle and Development

Flattie spiders go through a few stages in their lifecycle:

  1. Egg: Females lay eggs in a silk sac
  2. Spiderlings: Tiny spiders hatch from the eggs
  3. Juvenile: The spiderlings grow through several molts
  4. Adult: The spider reaches full maturity

Here’s an overview of their development process:

Stage Characteristics
Egg Eggs are laid in a silk sac
Spiderling Tiny spiders hatch from the eggs
Juvenile Spiderlings molt several times to grow
Adult Fully matured and able to reproduce

Flattie spiders generally have a short lifespan, with the sex determining the duration. Males live for around 6 months, while females may live up to a year.

Species and Genus

Selenops Genus

The Flattie spider belongs to the Selenops genus, which is known for their flattened bodies and unique hunting techniques. These spiders are commonly found in tropical and subtropical regions. Some interesting features of this genus include:

  • Flattened body allows them to hide in narrow crevices
  • Agile and fast-moving hunters
  • Nocturnal creatures actively hunting during the night

Different Species

There are several species within the Selenops genus, each with their distinct characteristics. Here are a few examples:

  • Selenops radiatus: Mainly found in the southeastern United States, this species varies in color from a light brown to a dark gray. It can largely be found in homes and other structures.
  • Selenops mexicanus: This species is native to Mexico and Central America. It has a distinct mottled pattern on its body, which camouflages well with its surroundings.
  • Selenops submaculosus: Native to the Caribbean, this species of Flattie spider has subtle patterns on its body and often lives in palm trees, hiding under bark.
Species Distribution Distinct Features
Selenops radiatus Southeastern United States Light brown to dark gray
Selenops mexicanus Mexico and Central America Mottled pattern on body
Selenops submaculosus Caribbean Subtle patterns, lives in palm trees

Observations and Research

Sightings Overview

The Flattie Spider, belonging to the Selenopidae family1, has caught the attention of researchers and entomologists worldwide. The World Spider Catalog2 provides information on these spiders’ sightings and identification.

Spider ID and Documentation

Spider ID3 is a platform where members share spider sightings, and it’s a valuable resource for documenting Flattie Spider occurrences. For instance, one Spider ID member reported a sighting in California4, contributing to a growing body of knowledge on this arachnid.

Entomologist Contribution

Entomologists, such as those working at the California Academy of Sciences5, have published studies on Flattie Spiders in journals like the Journal of Experimental Biology6. Their research offers insights into the spider’s characteristics:

  • Named by Latreille in 18197
  • Part of the Selenopidae family
  • Unique flat appearance

Identification Features

To help with identification, here are some key features of the Flattie Spider:

  • Flat body shape
  • Wide-set eyes
  • Fast-moving

Comparison Table

Flattie Spider Other Spiders
Flatter body Rounder body
Wide-set eyes Clustered eyes
Fast movement Varies

Human Interaction and Coexistence

Encounters with Flattie Spiders

Flattie spiders are generally non-aggressive and rarely encountered by humans. When they do interact with people, it’s often due to their habitat preferences:

  • Low foliage: Flattie spiders commonly reside in low foliage where they hunt for prey at night.
  • Under rocks or debris: These spiders can also be found hiding under rocks or debris in natural settings.

Flattie Spiders in Man-Made Structures and Natural Settings

Flattie spiders can adapt to various environments, including:

  • Man-made structures: Flattie spiders may find their way into homes and buildings, particularly in search of prey or shelter.
  • Natural settings: These spiders are native to regions like Madagascar and Australia, where they can be found in different types of foliage and landscapes. For example, they may inhabit bark on trees or rest near freshwater rivers, lakes, and streams.

Here’s a comparison table highlighting the differences between their habitat preferences:

Habitat Man-made Structures Natural Settings
Low Foliage Sometimes Yes
High Foliage Rarely Yes
Under Rock/Debris Rarely Yes
Freshwater No Near river, lake, stream
Bark No Yes
Regions Worldwide Madagascar, Australia

In conclusion, while Flattie spiders are rarely encountered by humans, they can adapt to different environments and can be found in both man-made structures and natural settings. The key to coexisting with these spiders is understanding their habitat preferences and taking steps to minimize contact, such as checking areas where they are likely to hide and being mindful of their presence in those locations.

Footnotes

  1. https://en.wikipedia.org/wiki/Selenopidae

  2. https://wsc.nmbe.ch/search

  3. https://spiderid.com/

  4. https://spiderid.com/sightings/

  5. https://www.calacademy.org/

  6. https://jeb.biologists.org/

  7. https://en.wikipedia.org/wiki/Pierre_André_Latreille

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Flattie

 

flattie!
Location: key largo, fl
December 4, 2011 8:51 pm
Hey guys! Here’s a cool flattie spider hanging out on my bathroom wall. I live in key largo and I was wondering if I could get more specific species info from you 🙂
Signature: wheezy

Flattie

Dear wheezy,
Thanks so much for sending us your photo.  From what we have been able to glean from BugGuide, Flatties are in the family Selenopidae, and new world species seem to all be classified in the genus
Selenops.  According to BugGuide, there are:  “7 species in BugGuide’s range (North America north of Mexico), but many species in Central America that can be possible imports.”  We are unable to provide you with an accurate species identification at the moment.

Letter 2 – Flattie

 

Subject:  I see these everywhere
Geographic location of the bug:  Southern Florida
Date: 05/07/2019
Your letter to the bugman:  I keep seeing these all over near my house and outside. Can’t identify it. Please help
How you want your letter signed:  Cory

Flattie

Dear Cory,
Spiders in the genus
Selenops are frequently called Flatties, and here is a BugGuide image for comparison.

Letter 3 – Flattie

 

Subject:  What type of spider?
Geographic location of the bug:  South Florida
Date: 04/16/2021
Time: 10:43 AM EDT
Your letter to the bugman:  What type of spider is this in my bathroom?
How you want your letter signed:  Jakob

Flattie

Dear Jakob,
This is a nocturnal hunting spider (does not build a web for snaring prey) in the genus
Selenops, commonly called a Flattie, and here is a BugGuide image that looks very similar.  According to BugGuide:  “This genus is found throughout the tropics and subtropics worldwide and can be found in southern parts of the U.S. ”  This shy group of Spiders is not a threat to humans.

Flattie

Letter 4 – Flattie from Kenya

 

Spiders
Location: Masai Mara, Kenya
December 22, 2010 5:01 am
Hi Bugman,
As you mentioned you don’t get many entries from East Africa, here are a few close-ups of the spiders I live with.
Picture 1: A ”Flattie” or ”Wall Spider” from the Family Selenopidae. Selenops spp.

Keep an eye out for more. I’ve got tonnes!
Signature: Zarek

Flattie from Kenya

Hi again Zarek,
We in no way want to discourage you from sending additional images to post to What’s That Bug?, but this particular email contains images of details of the heads of three different spider species, which means we need to divide it into three different posts, each with a truncated version of your email comments.  We are well aware that the eye pattern configuration is a critical identification key to many spiders, but we feel that our readership would benefit much more if this posting contained a shot of the entire spider for comparison as well as a “headshot” detail image.  Our readership would also appreciate a bit more narrative on the individuals, including the circumstances surrounding the sighting and any unusual observations you may have made.  Flatties are awesome spiders that get their common name because they have such a low profile and they and squeeze between tight crevices.  Flatties are nocturnal hunting spiders that do not build a web to snare their prey.  BugGuide has images of some North American species.

Hi Daniel,
I’m sorry. I didn’t even think about the difficulty you would have categorizing each image separately.  Didn’t mean to create extra work for you!
This particular flattie was one of the first spiders that got me properly interested in spiders.  He would sit on the floor next to me while I was sitting on the toilet (too much information??) and just seemed to be watching me.  He had obviously lost a few legs (as is evident in the photo) and so couldn’t move quite as quickly as others of his kind usually can.
As you say, they are usually nocturnal, but I usually saw this guy out in broad daylight.
Since then, I’ve come across many other flatties around my tent, but never had a good opportunity to get another good picture of one with all its legs still attached.

Letter 5 – Flattie from Panama

 

Subject: Is this flattie(?) really Selenops?
Location: Down Rio Chucunaque from Yaviza, Darien, Panama
April 14, 2017 6:33 am
I found this flat spider “squashed” against a small tree trunk in the Darien Gap in Panama. It seems to be the same as or related to the ones in the news a couple years ago that can glide from a treetop back to the trunk, which those articles called Selenops. The spider was 3-4 cm long with legs, and when I finally disturbed it, it scampered nimbly around the tree.
This was in dense forest
Signature: Peter H

Flattie

Dear Peter,
Selenops is a genus in the family Selenopidae, commonly called Flatties, that is also found in North America and is represented on BugGuide where it states:  “Selenops is from Greek selene (σεληνη)- ‘moon’ + ops (ωψ)- ‘eye, face’. Latreille translated it into French as ‘yeux en croissant’ which means ‘eyes in a crescent'” and though there is no diagram on BugGuide, the eyes on your individual do appear in a crescent form.  Additionally the morphology of your individual is very similar to the images posted to BugGuide.  The pedipalps on your individual lead us to believe it is a male Flattie.  Its camouflage is quite remarkable and we can’t believe you actually spotted it in a “dense forest.”  Flatties are hunting spiders that do not build webs.

Flattie
Flattie

Letter 6 – Flattie rescued from Arizona hotel room

 

Subject:  Found this beauty in my hotel room!
Geographic location of the bug:  Phoenix
Date: 01/14/2019
Time: 07:35 PM EDT
Your letter to the bugman:  I was laying on my bed in my hotel room looking at the ceiling and suddenly realized I was staring at a pretty good sized spider. I called maintenance for a ladder and the guy showed up with a stick and a wad of duct tape inside out on the end of it. I said I wanted it captured alive so we could release it and he promptly handed me the ladder and a trash can. After some coaxing I managed to get it in the can and released it across the street. It’s January in Phoenix, cool weather (65 by day, 40s by night, but since it was inside that might not matter as much). As you can see it has stripes, and it was almost perfectly flat against the ceiling. My guess is fishing spider but wondering what you think. Thanks for your help in advance!
How you want your letter signed:  Erich Walsh

Flattie

Dear Erich,
We have not awarded the Bug Humanitarian Award in some time, but discovering this Spider in a hotel room, calling maintenance and then capturing and releasing the Spider across the street certainly qualifies you as a bug humanitarian.  Your description that “it was almost perfectly flat against the ceiling” is acknowledged by the common name Flattie for Spiders in the family Selenopodidae, genus
Selenops, which can be viewed on BugGuide.  According to BugGuide: “This genus is found throughout the tropics and subtropics worldwide and can be found in southern parts of the U.S. In Sarah Crews’ 2011 paper, it is noted that there are quite a few unsorted specimens from all over the southwest (so it is best not to take the following ranges as concrete).”  Confusing this Flattie for a Fishing Spider is understandable.

Daniel,
Thank you so much for the identification and the bug humanitarian award! That’s good fun and feels great. You deserve an award more than I do though for being a public advocate for nature and helping people be a part of that.
All the best!
Erich

Authors

    by
  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

4 thoughts on “Flattie Spider: All You Need to Know in a Nutshell”

  1. this is really interesting & informaional site. Ty. I’m a 35 yr old N Florida native since birth, & am deathly scared of certain spiders-tho, I hv great respect for them, & didn’t ever kill 1, my whole life, until 34 yrs old, Bc I thought a hunting spider was a recluse-near my 5 yr old girl.
    Ever since my family moved back to my childhood town, in the countryside, & moved into a used double wide-we’ve been dealing with spiders way too much. Some r hunting spiders, some r defin recluses..& I cant risk them hurting my lil girl, so I kill them now, if inside the house & they seem threatening, at all. (I do take the lil less scary spiders outside, tho, ? when possible). How do u recommend spider-proofing ur home? Espec a double-wide? We hv most vents & holes under the house, stapled & duct-taped up pretty well, but I still worry.
    Should I put spider poison n all possible entries into home, & in any cracks/crevices, & maybe caulk all the holes up?
    Hopefully that’ll work.. bc we’ve been here less a year, & I’ve had this o deal with way too many big scary spiders..& my 6 yr old is scared ? so badly by them..that she asks about moving!
    (I know we can call an exterminator-next on list, if I have to.)
    PS. Peeps who say brown recluses don’t live in FL r SO WRONG! (& they do get bigger than a nickel—bigger than you’d think.)

    Reply
  2. this is really interesting & informaional site. Ty. I’m a 35 yr old N Florida native since birth, & am deathly scared of certain spiders-tho, I hv great respect for them, & didn’t ever kill 1, my whole life, until 34 yrs old, Bc I thought a hunting spider was a recluse-near my 5 yr old girl.
    Ever since my family moved back to my childhood town, in the countryside, & moved into a used double wide-we’ve been dealing with spiders way too much. Some r hunting spiders, some r defin recluses..& I cant risk them hurting my lil girl, so I kill them now, if inside the house & they seem threatening, at all. (I do take the lil less scary spiders outside, tho, ? when possible). How do u recommend spider-proofing ur home? Espec a double-wide? We hv most vents & holes under the house, stapled & duct-taped up pretty well, but I still worry.
    Should I put spider poison n all possible entries into home, & in any cracks/crevices, & maybe caulk all the holes up?
    Hopefully that’ll work.. bc we’ve been here less a year, & I’ve had this o deal with way too many big scary spiders..& my 6 yr old is scared ? so badly by them..that she asks about moving!
    (I know we can call an exterminator-next on list, if I have to.)
    PS. Peeps who say brown recluses don’t live in FL r SO WRONG! (& they do get bigger than a nickel—bigger than you’d think.)

    Reply
    • We are referring to the common name for this Spider and other members of its family Selenopidae. According to Arachne.org.au: “Wall crab spiders or ‘flatties’ have laterigrade (sideways-moving) legs. … They are commonly found on walls, under bark or rocks. They are swift, agile and usually difficult to capture. Most species are cryptic and blend with their surroundings.”

      Reply

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