Anchor ads are not supported on this page.

4S Ranch Allied Gardens Alpine Baja Balboa Park Bankers Hill Barrio Logan Bay Ho Bay Park Black Mountain Ranch Blossom Valley Bonita Bonsall Borrego Springs Boulevard Campo Cardiff-by-the-Sea Carlsbad Carmel Mountain Carmel Valley Chollas View Chula Vista City College City Heights Clairemont College Area Coronado CSU San Marcos Cuyamaca College Del Cerro Del Mar Descanso Downtown San Diego Eastlake East Village El Cajon Emerald Hills Encanto Encinitas Escondido Fallbrook Fletcher Hills Golden Hill Grant Hill Grantville Grossmont College Guatay Harbor Island Hillcrest Imperial Beach Imperial Valley Jacumba Jamacha-Lomita Jamul Julian Kearny Mesa Kensington La Jolla Lakeside La Mesa Lemon Grove Leucadia Liberty Station Lincoln Acres Lincoln Park Linda Vista Little Italy Logan Heights Mesa College Midway District MiraCosta College Miramar Miramar College Mira Mesa Mission Beach Mission Hills Mission Valley Mountain View Mount Hope Mount Laguna National City Nestor Normal Heights North Park Oak Park Ocean Beach Oceanside Old Town Otay Mesa Pacific Beach Pala Palomar College Palomar Mountain Paradise Hills Pauma Valley Pine Valley Point Loma Point Loma Nazarene Potrero Poway Rainbow Ramona Rancho Bernardo Rancho Penasquitos Rancho San Diego Rancho Santa Fe Rolando San Carlos San Marcos San Onofre Santa Ysabel Santee San Ysidro Scripps Ranch SDSU Serra Mesa Shelltown Shelter Island Sherman Heights Skyline Solana Beach Sorrento Valley Southcrest South Park Southwestern College Spring Valley Stockton Talmadge Temecula Tierrasanta Tijuana UCSD University City University Heights USD Valencia Park Valley Center Vista Warner Springs

Donovan knows his invertebrates

Dear Uncle Matthew and Aunt Alice:

Sponsored
Sponsored

We all know that our garden variety of snails leave a slimy trail on leaves when they move around. Buy why, when they traverse a cement sidewalk, is the track not a continuous one? It's almost as if the snail, upon reaching the sidewalk, is shocked and jumps, landing a short distance away, leaving slime, then jumps again, leaving a track that is slime, no slime, slime, no slime, etc. What mechanism leaves the no-slime segment of their track?

-- Ned in Point Loma

As that musty troubadour and scholar of invertebrate science Donovan once said, "First there is a mountain, then there is no mountain, then there is." He was talking about the snail upon his garden gate-- or maybe a caterpillar; the lyrics are a little hazy. But the snail upon your footpath moves the same way. Snails and slugs secrete a protective mucus from their undersides. Slugs move in continuous contact with whatever they're crawling on and leave an unbroken slime trail. Garden snails move like some caterpillars, hunching up their midsections and drawing their back ends forward. Thus the dotted line.

The latest copy of the Reader

Please enjoy this clickable Reader flipbook. Linked text and ads are flash-highlighted in blue for your convenience. To enhance your viewing, please open full screen mode by clicking the icon on the far right of the black flipbook toolbar.

Here's something you might be interested in.
Submit a free classified
or view all
Previous article

Temperature inversions bring smoggy weather, "ankle biters" still biting

Near-new moon will lead to a dark Halloween

Dear Uncle Matthew and Aunt Alice:

Sponsored
Sponsored

We all know that our garden variety of snails leave a slimy trail on leaves when they move around. Buy why, when they traverse a cement sidewalk, is the track not a continuous one? It's almost as if the snail, upon reaching the sidewalk, is shocked and jumps, landing a short distance away, leaving slime, then jumps again, leaving a track that is slime, no slime, slime, no slime, etc. What mechanism leaves the no-slime segment of their track?

-- Ned in Point Loma

As that musty troubadour and scholar of invertebrate science Donovan once said, "First there is a mountain, then there is no mountain, then there is." He was talking about the snail upon his garden gate-- or maybe a caterpillar; the lyrics are a little hazy. But the snail upon your footpath moves the same way. Snails and slugs secrete a protective mucus from their undersides. Slugs move in continuous contact with whatever they're crawling on and leave an unbroken slime trail. Garden snails move like some caterpillars, hunching up their midsections and drawing their back ends forward. Thus the dotted line.

Comments
Sponsored

The latest copy of the Reader

Please enjoy this clickable Reader flipbook. Linked text and ads are flash-highlighted in blue for your convenience. To enhance your viewing, please open full screen mode by clicking the icon on the far right of the black flipbook toolbar.

Here's something you might be interested in.
Submit a free classified
or view all
Previous article

The danger of San Diego's hoarders

The $1 million Flash Comics #1
Next Article

The vicious cycle of Escondido's abandoned buildings

City staff blames owners for raising rents
Comments
Ask a Hipster — Advice you didn't know you needed Big Screen — Movie commentary Blurt — Music's inside track Booze News — San Diego spirits Classical Music — Immortal beauty Classifieds — Free and easy Cover Stories — Front-page features Drinks All Around — Bartenders' drink recipes Excerpts — Literary and spiritual excerpts Feast! — Food & drink reviews Feature Stories — Local news & stories Fishing Report — What’s getting hooked from ship and shore From the Archives — Spotlight on the past Golden Dreams — Talk of the town The Gonzo Report — Making the musical scene, or at least reporting from it Letters — Our inbox Movies@Home — Local movie buffs share favorites Movie Reviews — Our critics' picks and pans Musician Interviews — Up close with local artists Neighborhood News from Stringers — Hyperlocal news News Ticker — News & politics Obermeyer — San Diego politics illustrated Outdoors — Weekly changes in flora and fauna Overheard in San Diego — Eavesdropping illustrated Poetry — The old and the new Reader Travel — Travel section built by travelers Reading — The hunt for intellectuals Roam-O-Rama — SoCal's best hiking/biking trails San Diego Beer — Inside San Diego suds SD on the QT — Almost factual news Sheep and Goats — Places of worship Special Issues — The best of Street Style — San Diego streets have style Surf Diego — Real stories from those braving the waves Theater — On stage in San Diego this week Tin Fork — Silver spoon alternative Under the Radar — Matt Potter's undercover work Unforgettable — Long-ago San Diego Unreal Estate — San Diego's priciest pads Your Week — Daily event picks
4S Ranch Allied Gardens Alpine Baja Balboa Park Bankers Hill Barrio Logan Bay Ho Bay Park Black Mountain Ranch Blossom Valley Bonita Bonsall Borrego Springs Boulevard Campo Cardiff-by-the-Sea Carlsbad Carmel Mountain Carmel Valley Chollas View Chula Vista City College City Heights Clairemont College Area Coronado CSU San Marcos Cuyamaca College Del Cerro Del Mar Descanso Downtown San Diego Eastlake East Village El Cajon Emerald Hills Encanto Encinitas Escondido Fallbrook Fletcher Hills Golden Hill Grant Hill Grantville Grossmont College Guatay Harbor Island Hillcrest Imperial Beach Imperial Valley Jacumba Jamacha-Lomita Jamul Julian Kearny Mesa Kensington La Jolla Lakeside La Mesa Lemon Grove Leucadia Liberty Station Lincoln Acres Lincoln Park Linda Vista Little Italy Logan Heights Mesa College Midway District MiraCosta College Miramar Miramar College Mira Mesa Mission Beach Mission Hills Mission Valley Mountain View Mount Hope Mount Laguna National City Nestor Normal Heights North Park Oak Park Ocean Beach Oceanside Old Town Otay Mesa Pacific Beach Pala Palomar College Palomar Mountain Paradise Hills Pauma Valley Pine Valley Point Loma Point Loma Nazarene Potrero Poway Rainbow Ramona Rancho Bernardo Rancho Penasquitos Rancho San Diego Rancho Santa Fe Rolando San Carlos San Marcos San Onofre Santa Ysabel Santee San Ysidro Scripps Ranch SDSU Serra Mesa Shelltown Shelter Island Sherman Heights Skyline Solana Beach Sorrento Valley Southcrest South Park Southwestern College Spring Valley Stockton Talmadge Temecula Tierrasanta Tijuana UCSD University City University Heights USD Valencia Park Valley Center Vista Warner Springs
Close

Anchor ads are not supported on this page.

This Week’s Reader This Week’s Reader